We took my wife's car to Evans Halshaw on 27 December 2017. They appraised the car and made an offer, which we accepted. We completed all the paperwork, and were guided through the process by the salesman. A week after they issued the signed purchase invoice, they are refusing to pay unless we give further evidence of my wife's address. They have a passport, the V5 and a copy of her bank statement , printed in the dealership, as requested by the salesman. They have the car - the V5 has been sent to the DVLA, they have all the information we were asked for at the dealer. How can we get our £5000? I believe we have a valid contract.