Disappointing service and outcome: 2 faulty units sent

I ordered a Mecer tablet from FirstShop early in January. When it arrived it wouldn't boot or turn on properly. I contacted them and they sent a courier to pick it up, and then agreed that it was faulty and asked if I wanted a refund or a replacement unit. Since I do want a tablet I requested a new unit. This was finally delivered a week ago and I immediately tested it, same problem. This time I said I want a refund, as it is now more than a month of back and forth and I still don't have a functional unit. Their courier picked up the second unit for investigation and I am currently still waiting for my refund. Very disappointing service and outcome. Every step in the process takes ages and there is no real concern for the customer's experience or needs.