redmi 3s prime seller techgadget

eBay is worst in dealing with guarantee related to mobiles they sell, I purchased Redmi 3s prime first I got late delivery secondly I received defective product, it does not support 4g sim although it was told on description, again customer care is pathetic, they asked me to visit customer care nd bring letter from them although when I asked service centre they r telling they don't provide service for products purchased from eBay, now my money is stuck, Seeley not picking up call, customer care not raising my claim for refund, it's truly cheating with customers,