A group of scammers have been targeting customers in Upham by ringing to say you have a problem with either your phone line or preference calling and claim that they can block nuisance calls
They give you the option to ring them back to confirm they are from BT on 01243 556774 or 01268 795243
They then ask you a series of questions and give you a named person who will follow up on your query.
Over a few days they ring again, asking if your nuisance calling problem has been resolved. Eventually they offer to block nuisance callers for a small fee and they obtain your payment details. Then they can then withdraw larger amounts from your account.
Advice from BT with regards to scam calls can be found here.
The ICO gives advice on reporting spam or nuisance calls, as does Ofcom