Cashier check sent in mail not received?

If a cashier's check sent in the mail has not been received, first check with the sender to confirm it was mailed and verify the address. You may also want to contact the issuing bank to report the situation and see if they can track the check. If the check is lost, the bank may have procedures for reissuing it, which could involve completing a stop payment request. Always keep records of your communications for future reference.