Elderly people have paid out thousands of pounds after being cold-called by an organisation claiming to be linked to social and health services in Stoke-on-Trent.
Representatives are even taking pensioners directly to the bank as they look to make a sale.
Stoke-on-Trent City Council's Trading Standards department has been receiving up to three complaints a day about the company and its "aggressive" sales practices since becoming aware of the problem two weeks ago.
And it has now teamed up with Staffordshire Police and NHS North Staffordshire to warn residents they could be paying over the odds for unnecessary products.
An investigation has now been launched into the company – which has not been named at this stage by the authorities – and its practices.
Trading Standards advice manager Val Edmonds said: "We think they are moving about, but they are targeting Stoke-on-Trent at the moment."
It is believed the firm, which is not local, moves from area to area, having obtained phone contact details for vulnerable people. Last week, calls were concentrated around Bucknall, but the problem has now spread city-wide.
After phone contact is made, the caller asks questions about benefits received, if the person is living alone and sometimes claims to be acting for Social Services. Residents are then being offered a mobility assessment and a sales visit is arranged.
During that appointment, an attempt is made sell expensive and unnecessary mobility products, including stair and bath lifts.
Ms Edmonds advised people never to give out personal information over the phone and said the proper authorities will always arrange a meeting.
She added: "If a contract is signed at home, the customer has seven days in which to change their mind and have their deposit refunded. But one person was told they must not cancel or the salesman would get into trouble. People are also being given the offer of going to the bank."
Derek Pamment, associate direct of operations at NHS North Staffordshire, urged residents not to agree to any visits from these companies.
He added: "NHS staff will always show their identification badge before entering a person's home and are happy to have their identity verified."
A Staffordshire Police spokesman said the force had received a number of calls about the company.
He said: "We are working with Trading Standards officers and urge anyone who is contacted by a company offering mobility products – even if they have made an appointment – not to allow them in.
"Residents should seek support from family or neighbours and, as always when anyone calls unexpectedly, keep the chain on. If you still need help, call the police immediately."
If you have recently received a similar phone call or visit from a mobility company, you can call Stoke-on-Trent Trading Standards on (01782) 232065 or Staffordshire County Council Trading Standards on 07773 792252. Staffordshire Police's non-emergency contact number is 0300 123 4455.