I run a local tyre shop. recently a customer rang up to buy some tyres. I ordered the tyres in for the customer and the customer paid for them over the phone. A couple of days later someone came to collect the tyres for the customer. Now i have a Chargeback letter from worldpay telling me that the customer never bought the tyres. I sent proof of the transaction to worldpay and they responded telling me there was nothing they could do and i had to pay the money back. I cannot get in contact with the customer, and the police refuse to help. What should i do?