Financial loss on a claimant's existing product
Report the loss to your bank/credit card company and notify the police if you are requested to do so. At this point, once all security checks have been complied with, the bank may suggest setting up a new debit card or transferring money into a new account whilst the fraud is investigated.
If you have not already done so, contact Royal Mail to check whether there has been a redirection order on your address.
Obtain a copy of your credit file to see whether this has been affected by any fraudulent activity.