It is "totally unacceptable" that people owed thousands of pounds back from the Government are having to wait more than a year to get their cases reviewed, an MP has said.
Labour's Alex Cunningham branded the Independent Case Examiner (ICE) "an absolute nonsense" as it emerged it was taking over 12 months on average to resolve complaints against the Child Support Agency (CSA).
The Stockton North MP spoke out over constituent Carl Davey, who has been waiting two years to get £43,000 back from the CSA - and now faces months of further delays while ICE reviews the case.
ICE handles complaints against a whole host of Department for Work and Pensions (DWP) services, such as CSA, Jobcentre Plus and the Disability and Carers Service.
A DWP spokesman said complaints are rare and resolved "as quickly as possible".
Mr Cunningham said: "It's an absolute nonsense that people are waiting for well over a year on average, when they've spent several months going through a series of loopholes in the system.
"It takes many months to go through it, you feel you've been wronged, and then you find it's going to take a year to get it resolved.
"It's totally unacceptable and it must be reflective of the cuts in people working there.
"There's got to be a resource implication. It's taking an average of a year and over for some people, who are entitled to quite large sums of money."
In March 2015 a tribunal ruled that Mr Davey had overpaid his child support by £43,000.
Having been told he would be paid the money back within eight weeks, Mr Davey says the CSA then cited a loophole which would entitle him to just £18,000.
After inquiries by Mr Davey and his MP Mr Cunningham, they launched an appeal against the case to ICE late last year - only to be told to expect another lengthy wait.
Mr Davey said: "The judge said you've won your case, they have to pay you back all that money, but it's gone on too long now.
"With this other thing now, saying that there's not enough staff sorting out cases, it feels like I've been strung along."
Responding to a written parliamentary question from Mr Cunningham, work and pensions minister Caroline Nokes said: "In the 2016 calendar year the average time taken to process complaints relating to the Child Support Agency, from the point the complaint was accepted for investigation to case closure, was 53 weeks."
Further figures disclosed by Ms Nokes show 265 cases took longer than 12 months to resolve, compared to 136 that took less.
A DWP spokesman added: "Complaints are rare and we always aim to resolve any issues as quickly as possible directly with claimants.
"The Independent Case Examiner is there to look at complaints which can't be easily resolved, and as such are often complex.
"The old CSA failed families because it was overly complex and did not provide taxpayers' value for money which is why we are replacing it with the new Child Maintenance Service."