A former unpaid carer has urged welfare officials to “get their act together” after they continued to pay him carer’s benefit for six months after the death of his husband, potentially landing him with debts of more than £1,300.

Chris Farrell, 65, who claimed carer’s allowance for four years while providing full-time care for his late husband repeatedly tried to get the Department for Work and Pensions (DWP) to stop paying him the £86.45 a week benefit.

Farrell said his anxiety over the growing benefit payments in his bank account – and uncertainty over whether he would be punished despite following the rules – had left him distressed and unable to move on with his life.

The DWP said on Friday it would write off Farrell’s overpayment – meaning he does not have to pay back the carer’s allowance income paid to him as a result of official error – after the Guardian approached officials with details of his case.

The Guardian is aware of five other cases where carers said they were unable to stop carer benefit payments despite informing the DWP that they were no longer caring and neither wanted nor were eligible for the benefit.

A carer served an overpayment demand – a request to return benefit income wrongly paid as a result of what officials deem is carer error – would have to repay it along with a £50 civil penalty fine. In extreme cases they would be at risk of fraud charges.

“The death of my husband was a hard enough blow to deal with. This was made so much worse by having to repeatedly tell DWP to stop paying the allowance – it was a constant reminder of my life ‘stopping’ for four years while I was a full-time unpaid carer for him,” said Farrell, who said he would donate the money to a food bank.

He added: “The DWP needs to get its act together to ensure when a claimant advises them of a change in circumstances they action the information efficiently so overpayments and potential penalties are not left hanging over someone who tries to do the right thing.”

Alongside the stress for carers, the cases raise concerns taxpayer money is being misspent – and potentially having to be written off – because of DWP failure to routinely act on reported changes in circumstances.

Cases identified by the charity Carers UK include:

• A carer who has accumulated more than £2,000 of unwanted carer’s allowance since their mother went into a care home 10 months ago. They said they had contacted the DWP to cancel the benefit five times, by phone and online form, to no avail.

• A carer who found it impossible to get the DWP to stop carer’s allowance payments despite reporting over a year ago she had taken on a new work contract and was no longer eligible for the benefit. She had been overpaid more than £2,650.

• A man trying to manage work and care for his father, who claimed carer’s allowance for several months after being made redundant, has been unable to stop the benefit despite telling officials repeatedly he no longer needed it after finding a new job.

Campaigners said the cases highlighted continuing DWP systems flaws that made it hard for carers to securely report changes in circumstances affecting their benefit eligibility, leaving them at risk of penalties and causing distress and anxiety.

Helen Walker, the chief executive of Carers UK, said: “Despite doing everything expected of them, carers continue to receive payments they know they are not entitled to with no clear information about when, or if, recovery action will begin or how much they will ultimately owe.”

“Carers tell us that receiving money they know is not theirs to keep creates confusion and makes it difficult to budget or plan for the future. They are left with an ever-growing worry of potential debt hanging over them,” she added.

Carers are required to inform the DWP when they start or stop caring for someone, take up a new job or earn more than the allowed weekly earnings limits, or change address or marital status.

A Guardian investigation has revealed hundreds of thousands of unpaid carers were unfairly landed with hefty debts in recent years after DWP system failures meant they unwittingly ran up repayable carer’s allowance overpayments.

An official review of carer’s allowance last year found DWP backlogs and record-keeping issues led to carers being sent overpayment notices because their reported changes in circumstances, made months or years earlier, had been ignored, deleted or lost.

The review, by the disability rights expert Liz Sayce, recommended the DWP refund carers penalised by record management failures. The DWP agreed, but is yet to set out plans on how it will do this, or estimate the cost of repaying affected carers.

The DWP has previously sought to blame the spiralling numbers of carer’s allowance overpayments in recent years on carers it claimed had neglected to inform them of changes in earnings that affected their eligibility for the benefit.

This was rejected by the Sayce review, which said confusing, impenetrable and inefficient DWP systems were largely responsible for a tsunami of overpayments that amounted to hundreds of millions of pounds over five years.

Farrell, a podiatrist who lives in Gloucestershire, said he had called the DWP’s bereavement line in December and was assured his husband’s state pension and attendance allowance would be stopped and the carer’s allowance unit informed.

However, by March he realised the carer’s allowance payments were continuing beyond the eight-week grace period. He contacted DWP three times, through an online form, by phone and registered letter to stop the benefit, without success.

A DWP spokesperson said it was “very sorry to hear about Mr Farrell’s situation”, adding it intended to make further changes to modernise carer’s allowance.

“Once a carer’s allowance claimant has correctly reported a change in circumstances, their responsibilities are discharged – with any overpayments made by DWP written off as official error.

“We remain determined to make carer’s allowance fairer and simpler, so that it works for carers like Mr Farrell, who do so much for our society.”