HTC India — Htc 820 motherboard got damaged

Address:

Gautam Buddh Nagar, Uttar Pradesh, 201301

I bought htc 820 worth rs. 24, 000 mobile in the month of jan'15 and same my brother bought htc 620 rs. 17, 000. 10 days before suddenly my mobile stopped working and last month my brother mobile stopped working. Mobile were out of guarantee as its crossed 12 month but its been only 18 month. We went to service center and now they are saying mother board got damaged for both mobile. Same issue faced with some 1-2 my known person that mother board damaged which cost same like mobile only. I asked to htc center people they said that madam its an electronic device my concern is that is that the product quality of htc directly mother board got damaged which is not affordable. Please help.