A home care company has lost its contract with Cambridgeshire County Council.
Appletrees Homecare in Bar Hill provided help to 120 elderly people in their own homes.
The termination of the contract came after an inquiry by the council and the community services NHS Trust raised concerns about the quality of care.
The firm's carers will be offered jobs with Home Choice Care which has taken over the contract.
A recent Care Quality Commission report into Appletrees Homecare gave it a zero rating and the county council said it had decided to terminate the contract after "an investigation into concerns raised about the company's ability to deliver the service commissioned".
A joint statement from Cambridgeshire County Council and Cambridgeshire Community Services NHS Trust confirmed the contract was ended at 1200 GMT.
"This decision has not been taken lightly," the statement said.
"The welfare of vulnerable service users is of paramount importance to us and we recognise that this change may be a very unsettling experience for service users and their families.
"We are working closely with Home Choice Care to make the transfer as smooth as possible and have written to all service users to explain the changes taking place."
Home Choice Care has set up a freephone number - 0800 298 1398 - to provide service users and their families with a rapid response to any concerns or questions they may have.
No-one from Appletrees Homecare was available for comment.