Act fast: the sooner your bank knows, the better the chance of stopping the payment. Then report it, so police can link it to other cases.
Call your bank on 159. Then report it: Report Fraud on 0300 123 2040.
If you live in Scotland, report fraud and cyber crime to Police Scotland on 101.
Forward scam texts to 7726 (free on every network). Forward scam emails to report@phishing.gov.uk.