We repaired a car and parked it outside waiting for the owner to pay before he collected the car. We never let cars go unless we receive payment and if a customer wants to inspect our work we always send an employee with the keys so that the customer cannot simply drive a car away until our invoice is paid.
Unfortunately the customer, seen on CCTV, returned with a duplicate key and drove the car away without paying our invoice. We called him in the morning to say the repair had been completed; he came in the afternoon and took the vehicle.
What can we do?