HTC mobile with manufacturing defect. Review on HTC Desire 828 Dual Sim

I had bought a brand new HTC Desire 828 Dual Sim phone in the month of June 2016. Since that time it has been regularly getting hanged and not working properly. It has also been send to the service center for repair within first two months itself but time and again it causes problem. Its really frustrating and annoying to purchase a new phone and consistently send it for repair and even can't use it. Also the HTC customer care has provided me with no resolution even after the phone is in warranty. I demanded HTC to replace the phone as it has a manufacturing defect and the phone is still under warranty but they refuse to replace it. I am feeling really annoyed now that I have purchased such a cheap defective product and don't even used it for two months after spending so much of money. If anyone want to waste or garbage their money then only they buy HTC products.