The cross-party Commons Public Accounts Committee has accused Atos of providing "incorrect and potentially misleading" information about its capabilities when tendering to carry out claim assessments for the Government for the PIP scheme.
The firm has since agreed to end its contract early.
The DWP has let down some of the most vulnerable people in our society, many of whom have had to wait more than six months for their claims to be decided.
The personal stories we heard were shocking... a claimant requiring hospital intervention as a result of the stress caused by the delays suffered, and another claimant who was unable to afford the specific diet required for diabetes and gastric problems while waiting for a decision.
Some claimants have been forced to turn to food banks, loans and charitable donations to support the extra costs of living associated with their disability.
MPs expressed alarm that the average waiting time for terminally ill people to receive a decision was 28 days, 180% longer than originally expected.
The standard of service for claimants had been "unacceptable", with assessors cancelling home visits at the last minute, and failing to turn up after individuals travelled to assessment centres.
More top news
Soliciting of clients by sex workers should no longer be a crime, according to new recommendations made by Home Affairs Select committee.
Theresa May's bid to become Tory leader has won the backing of senior cabinet ministers including Michael Fallon and Patrick McLoughlin.
A 19-year-old has officially become the UK's youngest airline pilot after fast-tracking his way to a seat in the cockpit.