Mansfield District Council is reminding residents not to give any personal information to callers.
This follows a report that an elderly woman living in Mansfield received a phone call on Wednesday 12 April about claiming back Council Tax. She was told it would cost £77. The woman did not give any information to the caller and instead hung up.
Telephone scams such as this are known as "vishing". This one involves crooks calling residents - usually pensioners - to say they are entitled to a Council Tax refund often worth thousands of pounds.
However, in order to receive the refund they need to pay an administration fee in advance. This normally ranges between £60 and £350. Once residents have provided their details for the payment, the person to whom they spoke is then impossible to contact.
When the refund does not arrive, victims often phone their council. It is at this point the authority confirms that they know nothing about it and that the person has been a victim of fraud.
If you think you have been a victim of fraud, hang up the phone and wait five minutes before you call your bank or card issuer to report the fraud. This delay is advisable because fraudsters sometimes keep the line open and they could hear your next conversation until the line clears. Where it is possible, use a different phone line to make the phone call.
To report a fraud, call Action Fraud on 0300 123 2040 or visit www.actionfraud.police.uk/report_fraud