Residents in East Yorkshire have been targeted by a council tax scam, trading standards has said.
Property owners have complained of a company telling them they have been in the wrong council tax band since 1993 and are due a refund.
The company then arranges an appointment requesting a £165 fee and commission of any refund awarded.
East Riding of Yorkshire Council said the company, operating through leaflets and telephone calls, was a scam.
Colin Briggs from trading standards said: "Property owners who are approached unexpectedly over their council tax valuation must simply say no.
"By far the majority of properties are, despite the claims of this company, in the correct banding."
Mr Briggs said if taxpayers believed they were in the wrong council tax band they should contact the Valuation Office Agency.