A former worker at call centre giant Concentrix has said the company is not at fault for losing a multi-million contract with the taxman, saying HM Revenue and Customs' "poor systems" are to blame.
The ex-employee, who was let go last week, told the Belfast Telegraph it had been "tough and stressful" for the workforce since the news broke.
And she said more job losses were likely when the contract comes to an end next May.
Concentrix, which employs more than 1,800 staff in Belfast, was given the £75m HMRC contract to reduce fraud and error in the tax credits system.
However, following a barrage of complaints over its handling of the job, the deal will not be extended when it comes up for renewal in 2017.
Last week 150 staff on temporary contracts were laid off.
The Government said Concentrix had "not been providing the high levels of customer service that the public expect and which are required in their contract".
But the ex-worker, who didn't wish to be named, said the blame lay with HMRC.
"I don't agree that it was Concentrix's fault. It's the HMRC's systems - everything needs updated," she said.
"They need systems to be able to take on information much quicker.
"It takes up to 48 hours. The staff are trained in exactly what they have to do. We worked on behalf of HMRC carrying out compliance checks. Sometimes you would be on the phone, or off the phone working on cases.
"I enjoyed it as a company, and there was good morale in the business."
The former employee claimed that once staff had dealt with and processed a case, as well as the massive delay, the systems used by the Government body were not up to scratch. She added: "After we were closing cases off... it then sits in a sort of limbo stage."
Around 500-600 Belfast staff had been working on the contract. But some Concentrix workers say it is "unrealistic" to think all can keep their jobs, and dozens more could be let go once the contract ends.
"They have been told it is going to be ending in May," she added.
"Concentrix said they are going to try and replace them, with different campaigns, but I can't see that being realistic."