Shoppersstop.com — Product not delivered, no refund

I ordered a product which was never delivered and it showed delivered in my account. Reached out to shoppers Stop they took 20 days and said please ask your neighbours. We have delivered. No proof of delivery. Have been asking and need my refund immediately. I don't even want anything else . First they asked for you want refund or another order and then changed their statement to go and ask neighbours.
In the first place I only placed this order because they had given me credits online and if I didn't use my credits they would make it zero in 3 months. Which is my money - and they can't eat my money. But they did twice before I had to "request" them to give my credits back.