@home online team doesn’t want to refund me for an order they cancelled

Made a purchase online on the 16th December. The order was subsequently canncelled by the @home team because they had oversold the item online. To date they still have not refunded me and say that they did not take the money for my card. This money is sitting in my pending transactions and the bank will not release if without confirmation from them. @Home says they can’t assist me further and I must sort this out. Numerous attempts to get a hold of a manager or the manager’s manager have not been successful. Fatima has been assisting and on Tuesday 15th Jan she said she will resolve the matter and get back to me however today 18th Jan she still hadn’t and I had to phone. Poor service from the online staff! Please can I just get my refund!