Dozens of staff have been plunged in to debt by their employer after a five year overpayment blunder.

Cordia’s reablement staff, who help people adjust to independent living at home, were notified of the “unfortunate error” on Saturday.

Around 56 staff received a letter from Cordia, an arms-length company of Glasgow City Council and the city’s biggest home care provider, telling them they had been overpaid and their their salaries would be reduced by more than £1400 a year.

They were told their payments for non-standard working hours (NSWP) for early morning and late night shifts had been miscalculated.

The error is believed to have been in place for around five years, with staff now owing the firm up to £5000.

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Cordia has offered employees a loan to cover the debts and say they will start reclaiming the cash from their salaries on September 27.

The letter read: “Unfortunately, I must now advise you that the impact on your pay is that your NSWP payment will reduce by £1461 pro rata per annum.

“As it is also recognised that this error will have a financial impact upon you. Cordia can assist you by providing a short term loan.”

Staff have been left in a state of panic, and say the error will leave them short of cash to pay their bills and buy food each month.

One employee, who did not want to be named, said: “We have all been worried sick all weekend after receiving this letter, conveniently when the office is closed and we can’t ask questions.

“If they decide to make us pay back what they are calling overpaid money it will cause hardship for a lot of us.

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“Some of us will end up owing thousands.”

Trade unions have blasted Cordia bosses as”shameful”.

GMB Scotland Organiser Louise Gilmour said: “What Cordia have done here is nothing short of shameful, an attempt to suppress our members campaign for pay parity by driving down wages for everyone.

“Unnecessary fear and panic among our members in the reablement team has been stoked by the prospect of a significant amount of money being cut from their incomes, as you would expect if you woke-up on Saturday morning to open a letter from your employer stating as much.

“Our message to our members is clear: Do not agree, respond to or sign anything connected to this threat as we are working with our lawyers to check the legality of Cordia’s actions.”

A spokesman from trade union Unison said they have contacted the incident was “another example of Cordia not paying their staff correctly”.

A Cordia spokesman said: “The GMB raised a collective dispute intimating that they believed a number of their members had been underpaid, in non-standard working points per hour (NSWPH), using the Reablement Service as the benchmark.

“The GMB were unsuccessful in their claim, but this collective dispute highlighted that a number of staff had in fact been overpaid. The overpayment is linked to the additional payments staff receive for working on a seven days on / seven days off basis across a work pattern.

“Once this had been highlighted, Cordia carried out a detailed analysis of who this affected. The investigation revealed that 34 Reablement staff had been underpaid, and these staff will now be given what they are due in a lump sum.

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“However, it was also identified that 54 members of staff had been overpaid. We have now written to these staff members, apologising for this and offering a short-term loan while they adjust to their new pay levels, which they will see from their next pay at the end of this month.

“Meetings will now begin to take place with staff to discuss individual overpayments, and a sensitive and reasonable approach will be taken for making appropriate arrangements for repayment.

“We understand that this will be disappointing for staff who lodged this collective dispute and regrettably, on this occasion, Cordia had no alternative but to address this issue moving forward with the staff who have been directly affected.”