Pathetic customer service Pavillion BT GAMES

Purchased a PS4 controller on 27th November 2020. The controller became faulty. I took it back to the store today and December 2020 and was told that they needed a video showing that it was faulty. I sent one in just now only to be told that head office is closed and I can't have a refund. They can't replace the controller as there is no stock. The staff on site do not have authority to give a refund but... The people who do are unavailable! So my son must spend the next few weeks unable to play on his Playstation. What sort of ridiculous set up is this????