BASH (STERNS) WANTS A BANK STATEMENT TO ISSUE A REFUND!

I have had mixed experiences with Bash but the latest takes the cake. I took advantage of a sterns promo offer on watches for a birthday present. However, the watch was delivered to me broken. There wasn't a store near me that had the item which i still wanted. I contacted Bash support who asked for pictures and processed the pick up quite fast. However, the issue now is with the refund. They were happy to take my money (and obviously I had some!) otherwise I wouldn't have received the items. Now to get a refund I must send them a 3 month bank statement with my details! Have you ever heard of such twaddle?? Never mind that I have done refunds through Bash before without any hassles or requests for statements. The agent handling the support query, some person named Ordaal, keeps repeating the same thing to me every day even though I requested to speak to someone senior. She says that jewellery returns are processed manually. How is that my problem? Bash should not be selling jewellery if their systems are not up to scratch. I dont even want to ask for a voucher because I never want to purchase from Bash again. Any advice on how to deal with these *******?