The switch-off of 192 has been a "fiasco", with new directory enquiries providers misled about the number of calls they were likely to receive and at least one case of "cybersquatting" emerging, one of the companies has told BBC News Online.
The company behind the 118119 service, 192.com, said telecoms regulator Oftel had hugely overestimated the amount of traffic that would flow from a message for callers to the old 192 number.
118118: First in the race to dominate the market?
BBC News Online has also discovered evidence of "cybersquatting" as new operators battle to gain an advantage over rivals, buying internet domain names based on rival 118 numbers and redirecting visitors to advertisements for their own services.
Alastair Crawford, chief executive of 192.com, said Oftel had turned the 192 switch-off into a "fiasco".
"Oftel had predicted that about 75,000 calls a day would be made to the new entrants through the redirection service," he said.
"In fact the actual redirect numbers are more like 5,000 a day."
Oftel denied it had issued any estimates, but a spokesperson said: "Some companies thought they would get that many calls from the freephone number.
"[But] it is only a small proportion of people using the follow-on from the free 0800 number given out on 192."
Redirected to BT
In another swipe, Mr Crawford accused some companies of using questionable tactics to gain an edge over rivals.
When asked why the 118119 website automatically redirects users to a BT website advertising its own 118500 service, he said BT had bought the domain name.
A BT spokesman said there was nothing "underhand" about such tactics "in a competitive environment".
In addition, visitors to www.118247.co.uk have found themselves automatically redirected to a site advertising the 118080 service.
Misjudgement of the amount of business has already lead to hundreds of job losses at Conduit (118888) in Wales and England and Teletech in Northern Ireland.
118888 axed jobs on Thursday
Mr Crawford said these were unlikely to be the last layoffs following deregulation.
"Firms relied on Oftel's dial traffic figures. We'll be picking up the pieces from that in the short term future."
So far, about 16 companies have launched services while 40 have been given permission to do so.
Some firms have said the switch has been a success. However most have refused to reveal precise numbers for traffic to their numbers because of their "commercially sensitive" nature.
The Number, operator of 118118, says it has 30-40% of the market.
Spokesman William Ostrom said: "It's going very well. Awareness of the number is the highest in the market with up to 80% recall, double that of the nearest competitor.
"In terms of volume we're taking hundreds of thousands of calls a day - well over half a million."
Mr Ostrom added that things were going so well the firm is taking on 200 more staff in coming weeks, and aims to have 2,000 employees by mid-September.
Share Comms, which runs 118499, and donates a share of its income to charity, said: "We are receiving the budgeted number of calls. We're quite happy with the way its going and hoping to raise a lot of money."
Telco spokeswoman Kelly Finlay said: "In the first week the service usage rose 124%. 118877 is doing well."
Onetel, which opted to give a free 192 service to customers rather than splash out on advertising, has also seen business increase.
Spokeswoman Carol Barnes said: "Figures we've just got back on the first week show calls to our 192 service more or less doubled."
Meanwhile, Conduit also said it was receiving "hundreds of thousands of calls a day" despite cutting 240 jobs on Thursday.
But the firm added it had taken on the extra staff to ensure it could handle all of its calls quickly, and so hang onto customers.
Spokesman Ian Twinn said: "We had expected calls to double after the 192 changeover, and they more than doubled."