there are numerous posts just like yours already on the forum
This is a well known scam. If you have the number you were calle from you can report it on bt.com/scams . you might also want to get call protect on your phone line . You can order this through your MY BT. It helps you to bar numbers that you dont want to contact you in future by calling 1572 and then selecting option 1
Oh, thank you for the heads up!
Please be aware that the scammers change the called from number (they use VoIP systems and spoof the number), so Call Protect is frankly of little use in the general case. Don't expect it to trap all the calls, as it will not.