A former Labour MP ordered to hand over almost £18,000 in mortgage expenses has claimed he was never contacted by the watchdog carrying out the inquiry.
Ivor Caplin, MP for Hove from 1997 to 2005 and a one-time defence minister, told the Guardian he had written to auditor Sir Thomas Legg.
But he added that he had received no reply, although next Monday is the deadline for making repayments.
Earlier this month, Sir Thomas said he had written to Mr Caplin several times.
When the expenses scandal unfolded in May, Gordon Brown asked Sir Thomas to look for mistakes made in expenses payouts approved by the Commons Fees Office during a five-year period.
More than 300 current and former MPs have been told to repay more than £1.1m in expenses from the past five years following Sir Thomas's investigations.
Mr Caplin faced one of the larger requests for repayments but in Sir Thomas's report it said: "No reply has been received from Mr Caplin to a number of letters sent to the address held by House authorities.
"In default of evidence to support payments for mortgage interest of £17,865.33 for 2004-05 and April 2005, I must regard these payments as having been invalid.
"Accordingly, my recommendation is that Mr Caplin should repay the whole of this sum."
But in a statement on Friday, Mr Caplin, who now works as a public affairs consultant, said: "I have received no communication from or on behalf of Sir Thomas Legg at any stage during his inquiry.
"As soon as I became aware that he had been trying to contact me, I wrote to Sir Thomas and I am awaiting a reply."
If MPs do not start paying back the money requested by Sir Thomas by the 22 February deadline, they face having it deducted from their salary, allowances or resettlement grant - paid to those who retire or lose their seats. It is not clear what can be done to retrieve money from former MPs who refuse to pay.
Meanwhile the Sun reports that Commons leader Harriet Harman objected to Sir Thomas's suggestion that he include references to rejected expenses claims in his report.
It reported that minutes of a meeting between Ms Harman and Sir Thomas before he began his review said: "The leader questioned how appropriate it was to cover items outside those which were actually paid for by public money - the main issue should be payback of those items claimed wrongly."
A spokesman for Ms Harman said she met Sir Thomas twice and "fully supports" his review and payback.
Some of the rejected claims made under the second homes allowance were published by the Daily Telegraph, which acquired leaked copies of claim forms and receipts - including Sir Peter Viggers' £1,645 claim for a "duck island".