Absurd Refund

We bought a part which took 3 days to arrive. On receiving the part, we realised it was incorrect. We then returned the part and now the parts division are wanting my wife’s ID, banking details and a letter from the bank in order to make the refund. They are also stalling saying they are waiting for the refund 1st. I’ve never heard of anything more ridiculous. It’s a straight refund which we are entitled to. WITHOUT ANY COMPLICATIONS.