HTC Desire 816 — Totally defected cell it is, no proper sound system, voice etc

Address:

Gulbarga, Karnataka

This is second time i am complaining. I am tired of trying to call htc company, customer care number who are not at all receiving call and not responding.
My friend received my new cell on 16th june. (I waited to receive it myself till 11th but it did not cum) because i was out of station from 11th june to 20th july. I came back 21st (5 days ago) and used my new cell for the first time but it is a defected one. On the first day itself i felt heartbroken because its sound system is not working. Im not able to use it from the first day itself to speak. No voice at all. If i call to ebay online shoppers they said the date is over to exchange it. Now tell me whats next. I want to complaint. Should exchange my cell or refund it as soon as possible. Do reply. . . Its not correct way to behave with cstomers. I am totally unhappy with the product. . .