A firm used by the government to cut tax credit payments has received calls from "suicidal" clients, the BBC has been told.
A whistleblower at Concentrix's call centre said most staff "weren't even trained" to deal with such calls.
He said staff were not offered counselling, but were instead told: "Have a smoke... you'll be fine."
But Concentrix said, in the case of suicidal callers, staff were trained in accordance with government guidelines.
It told the BBC's Victoria Derbyshire programme: "Our staff are supported as much as possible where we have encountered this type of scenario."
US firm Concentrix was awarded a £75m contract by Her Majesty's Revenue and Customs (HMRC) - the department responsible for collecting taxes and paying out certain benefits - to help cut tax credit fraud and overpayment.
Last week the company learned it would not have its two-year contract renewed once it expires in May 2017.
Single mother Nicola McKenzie said Concentrix had cut her tax credits after she was wrongly accused of being married to a dead 74-year-old man.
Now, a member of the company's staff has spoken about the experiences of staff at its call centre in Belfast.
The 600 workers were yelled at "every day" by clients, he said, with "people crying down the phone to you that they're down to their last bag of wipes, have no food in the fridge to feed their kids".
"We were dealing with people claiming they were going to commit suicide," the whistleblower said. "You had to try and keep them on the phone, while a manager phoned the police to get out to their address to make sure that they were OK.
"Some of the [call centre workers] that were dealing with the suicide calls weren't given the back-up, weren't given aftercare by our aftercare team. Most of the people weren't even trained in how to deal with a suicide call."
Concentrix staff received no "aftercare by our human resources team, or any sort of counselling, after a call", he claimed, adding: "They were just told, 'Go out. Have a smoke. Come back. You'll be fine. Deal with another 40 or 50 calls.'"
Advice on how to handle suicidal callers
While Samaritans stress their first and main advice is to contact trained professionals to help people experiencing suicidal feelings, if you do find yourself in such a situation, they offer the following advice:
- If you encounter someone who expresses suicidal thoughts or feelings, take what they say seriously and encourage them to reach out for support
- Someone experiencing suicidal feelings may feel it helps to have a person who can listen, empathise and support while they identify things that will help them feel calmer and more in control
- In terms of what to say, something as simple as, "It sounds like things are really tough for you at the moment. There are people who can help. Please reach out for support."
- If you are worried about someone, you can also suggest that you get in touch with Samaritans on their behalf. If they are happy for you to pass on their contact details, the charity will then give them a call
- People should be made aware that they can talk to their local GP - the key message is that they should reach out for support as soon as possible
If you are struggling to cope or would like someone to talk to in confidence you can contact the Samaritans by calling 116 123.
What are tax credits?
People may be eligible for Working Tax Credit, broadly, if they earn less than £32,969. If a person's income is below this level and they also have children they'll be eligible for child tax credit. Eligibility for working tax credit also depends on how many hours a person works.
The average award of tax credit is £6,340 per year. But it can be far more than that.
The whistleblower said he had also spoken to "hundreds" of low-income householders who said their tax credits had been stopped without receiving a letter from Concentrix telling them to provide information within 30 days or their benefits would be halted.
He added: "It couldn't be a coincidence, so many people calling in that haven't met each other saying that they hadn't received this letter... I personally have spoken to hundreds of them."
Staff were not "allowed to reinstate or even temporarily reinstate their benefits, their tax credits, until they provided information", he added.
Concentrix said it had completed a validation to confirm that all the advance warning letters that were expected to be sent out were sent out, and that it is satisfied with this process.
It said it acts in strict accordance with guidelines set and provided by HMRC.
"There has to be a process and our staff are not there to apply a discretionary judgement, or implement their own exemptions as this would lead to further issues," it said.
"We are contractually obligated to contact individual tax credit claimants based on information provided by HMRC," it added.
In a statement, Concentrix said its staff were trained in "exactly the same way" as HMRC staff.
It added: "It is important to realise that our staff are not counsellors and we would never position them as such.
"There are experts who should be involved in situations like these and our staff are trained to ensure those external experts, like the police, are engaged."
The company said its senior management team was "highly engaged" with both clients and staff and managers were "highly supportive" of the staff who carried out "challenging" work on behalf of HMRC.
HMRC said payments could only be stopped when there was "strong evidence" to support the course of action.
It said: "We provide Concentrix with cases which have been flagged as showing potential discrepancies, along with the data we hold and have received from third parties.
"Concentrix is then responsible for using their own internal checks to identify which of these cases they think require further investigation."
It said Concentrix writes to claimants asking for information to verify their claim and payments will continue if the claimant responds with the right information with the 30-day timescale.
The Victoria Derbyshire programme is broadcast on weekdays between 09:00 and 11:00 on BBC Two and the BBC News channel.