The Child Support Agency is under fire for failing to answer one third of telephone calls about its new system.
The CSA had been repeatedly criticised since it was set up in 1993
More than one million of around 3.3 million calls attempted in the 16 months to July were engaged, not answered or eventually disconnected.
The findings were obtained by Liberal Democrat MP David Laws.
Minister for the CSA Lord Hunt said the agency needed to "dramatically improve" and was due for a thorough review, but was already making progress.
The new child maintenance scheme was introduced in 2003, replacing the old one which government ministers called "unworkably complex".
BBC social affairs correspondent Kim Catcheside said the new scheme had seen many problems.
The most recent figures showed the scheme was less efficient at getting money to the children who needed it than the old one, she said.
The agency received more than 600,000 new applicants last year alone, with the figures showing that the equivalent of about two calls per case failed to get through.
Karen Christie, who lives near Aberdeen, has been trying to reach the CSA ever since applying for maintenance last December.
"It's my telephone bill, not their telephone bill," she told the BBC.
"From my perspective it takes up a lot of time because I'm utilising time at night that I don't have. Either that, or I call during the day when I'm suppose to be working."
'Root and branch'
Lord Hunt said: "The latest figures show that the agency is now demonstrating a steady level of performance compared to last year, but we obviously need to improve dramatically if we are to provide an acceptable service to our clients."
He said the chief executive and his team would carry out a "root and branch review" of the agency this autumn, which would be announced by the end of the year.
Since it started in 1993, the CSA has been dogged by controversy. In particular it has suffered computer failures causing severe payment delays.
The latest figures were revealed in a Commons written answer to a question by Mr Laws.
"It shows this is an organisation in chaos," said Mr Laws.
"That the computer technology doesn't work, that the administration is failing and also that the system is the wrong one.
"We ought to be thinking about whether actually the Child Support Agency in its existing format ought to be abolished and folded in with the Inland Revenue."
Have you experienced difficulties contacting the CSA? What can be done to improve the service?
The CSA is a total nightmare. The government introduced the 'new' fairer assessment system in 2003. Some parents without care, like me, are paying over £150 per month more on the old scheme. And there's no sign of when we will be transferred to the new scheme. The computer system has cost £450million! How can it be so difficult to work out if an absent parent owes 15%, 25% or 35%?A few calculators would be easier - and cheaper.
Mark, Hatfield Hertfordshire
Late payments and incorrect payments aside, even contacting the CSA is difficult. All letters get sent with a contact number for an office in Dudley when the case is handled from Birkenhead. Rude staff blame you for ringing the wrong number and then refuse to give you the name of the person you need to speak to.
Andrew Brash, Manchester, UK
I have found at times it can take up to 20 minutes to get anyone to answer the phones (which doesn't put you in a good frame of mind to begin with!) When you finally get through nobody can help you and you are promised a call back which never arrives!
Luci Wigmore, Newbury, England
I have been with the CSA for seven years and they have only just managed to get me three months money, which has now stopped because the ex has left work again (3rd time). It is pretty obvious he will do anything not to pay, he owes me about £7000 in back payment. CSA are way to lenient on the fathers and even employers who cover up friends and relatives working for them. Everybody has a national insurance number, so why can this not be used in tracking these fathers down? As soon as they sign on or start a job, this should flag up on the CSA tracking system. How much money would the government save in the long run, if they actually managed to get these missing parents to pay for there children! Never have I experienced so much stress having to deal with this service. Something needs to be done NOW!
Lisa Nanton, Enfield
The CSA is a source of frustration to my partner and I can sympathise with the need for a central agency to ensure that a contribution is made towards care of their children. However, like most "runaway trains" it is very difficult to manage well, and ensure staff security. It would be useful if cases could be assigned to one single point of contact who would at least know some of the history of the claim rather than each time having to be repeated. Delays in changing cases from the old to the new system is taking far too long, this encourages inequalities in payment levels. Added to which having to try and understand some of the strong Belfast (call centre for this region) accents whilst attempting to explain, just adds to the stress levels.
I have been trying for the past nearly three years to get the father of my child to pay. I contacted the CSA when my daughter was born, and I got a letter of confirmation that my application had been received. This was the last I heard from them. I phoned them every two weeks for an update, and "someone else was now dealing with my case". For the past nearly 3 years, i have no outcome. The battle still goes on.
Z, Edinburgh, Scotland
Never mind the new system being bad. The 15% across board payments are not available to old cases reviewed before April 2003. So we have to suffer paying more average 25% rather than having a chance to pay 15%. Why do you keep concentrating on the people who aren't getting paid? What about the people who pay and take care of their kids but don't get a chance to pay the 15%? The system is good but computers hopeless but we old-style payment fathers get stuffed both ways. But that isn't a story is it? Lord Hunt explains this by saying is would be mad to swap over to the new system due to its problems...so we have to suffer because the government got a bad computer system. Oh yes who suffers from all of this.... my daughter.
Stewart Davidson, Bristol
The CSA is a disgrace. It is, and never was, designed to put children first. Consequently, it is at war with parents whom do. It should have been scrapped years ago and that this hasn't been done is grotesque. Its failure is not a consequence of a broken computer or irresponsible parents, but of disgraceful legislation implemented by appalling staff. In three years, I have spent in excess of 1200 hours of soul-destroying nihilism on the telephone to the CSA. It treats parents, not as human beings, but as collections of body parts capable of producing mathematical results, money and those responsible for this national scandal, be they politician or civil servant, must be brought to book.
D McKeever, Aberystwyth, UK
It's a nightmare. I've hung on for forty minutes before the machine has said nobody can take the call and disconnected it. You always have a long wait, even if you put your national insurance number in as they ask you to.
Anne, Chertsey, Surrey
I have had many problems with the CSA. One time it took me 40 minutes to get through only to find they put me through to an answering machine. They never seem to get the level of payments correct and arrears. I even had 4 calls from them claiming I was the parent of a girl and a woman who I had never heard from who lives in Liverpool, they never apologised, never received any letters from them, and this caused a lot of stress for me and my current girlfriend, having to pay maintenance to a girl I have never heard of. My girlfriend has also has a lot of trouble from the CSA. They regularly pay her late (often 3 weeks later) and she relies on that money to support her and children. When she eventually gets through to them (through sheer determination and desperation) they can't tell her when her payment is due and when they do promise her, it doesn't go into her account. Every time she talks to someone at the CSA they tell her a different story. I think the CSA should be scrapped. The maintenance due to a child should be deducted from a persons pay and paid to the tax office who then credit the account of the correct person.
Paul Hannon, Ashington