Sony India — My sony xperia z3+ in not working well

Address:

New Delhi, Delhi, 110001

This is yuvraj singh mob. [protected] having sony xperia z3+ purchased rupees 25000 from authorized service center, now my phones left side touch not working well, some alphabets like r, f, c, and many others not works at all. I went to near service center and they do what they can do and lastly said u need to change your full display. And the cost is 7500. My question is that when my phone is never dropped not a single scratch nothing at all, then what is my fault, when i google this problem i found no. Of peoples who owned xperia z3+ is facing the exact same proplem so this must not be customer fault this is the device problem and its your duty to get rectify this rather to blame customer. I just want a serious action against sony.