Thousands of parents were wrongly charged over a 10-year period as ministers face calls to act
More than 24,400 parents were overcharged by the Child Maintenance Service (CMS) over a 10-year period, with total overpayments reaching £4.3million.
The errors, which occurred between 2012 and 2022, were partly caused by computer faults within the Government-run agency.
The CMS, which operates under the Department for Work and Pensions (DWP), has the power to withdraw money directly from people's bank accounts and provides services to more than 800,000 parents across the UK.
The wrongful charges have also been linked to the deaths of two fathers who took their own lives after they were unable to meet inflated child maintenance demands.
Some separated parents were reportedly asked to pay thousands of pounds more than they actually owed each month.
More than 80 people told the Daily Mail they had repeatedly challenged incorrect charges but claimed the CMS failed to resolve their cases despite lengthy disputes.
Several parents described the experience as an "ongoing nightmare", with some alleging they are still being pursued for debts that courts have ruled they do not owe.
Child maintenance payments are intended to help cover the cost of raising children following a family separation, including expenses such as food and school uniforms.
Contributions typically range between 12 and 19 per cent of a parent's gross weekly earnings.
Payments usually continue until a child reaches the age of 20 or completes full-time education.
Liberal Democrat leader Sir Ed Davey criticised the agency's handling of the issue.
The allegations have prompted comparisons with the Post Office Horizon scandal, in which faulty computer software contributed to widespread miscarriages of justice.
Minutes from a meeting of CMS directors reportedly showed staff had raised concerns about "IT issues" within the service.
The Department for Work and Pensions rejected claims that the agency was affected by widespread technological failures.
A DWP spokesman said: "There are no systemic IT glitches within the CMS, and these claims are misleading and untrue."
The department said system upgrades carried out in 2018 to address issues including inadequate storage capacity resulted in slower response times.
However, it said those issues did not affect payment calculations and had been resolved by the end of that year.
The DWP said assessment accuracy rates had remained "consistently close to 100 per cent" and noted that parents who disagree with a decision can appeal to an independent tribunal.
The department also confirmed it had contacted those affected by the overcharging.
It said £2.7million of the £4.3million in overpayments had been repaid by February 2024.
