Just give my refund!!!

Purchased a wifi ups from them which was defective and logged the request for return. It's been such a mission getting this defective product returned as their refund department is so inefficient. They never respond even if you give then the 72 hours they request..then they request 5 days which was also given...Eventually managed to get the product returned(they sent courier without notifying me . I had to ask the courier to come tthe ext day as i wasn't ware they were coming so i never had the device with me) amd now I'm struggling to get a refund!!!! And again no.reaponse After so many messeges have been sent! Received the product 27th feb it's now the 11 April and and I have no device and no product! It's absolutely ridiculous that there has been no communication from their side. Will never use this company again