A universal-credit claimant who featured in a government film to promote the reform now says the system is riddled with computer problems and could make people destitute.
In the Department for Work and Pensions (DWP) advert, Daniel Pacey explains how the reform helped him to find work.
But he now says a six-week delay before the first payment and subsequent monthly payments are "a nightmare".
Mr Pacey, 24, from Wigan, Greater Manchester, said: ''It might be easy for a government minister to make their wages last a month. But I'd like to see them make £250 last four weeks while looking for work."