Blackberry Bold 9900 — Network Problem

Address:

Sundargarh, Odisha

I have a complain regarding network.I have purchased the phone on 29 th july 2012 and the problem started day after it.
Its just stp working after use of 4 -5 hrs, i mean i used to receive the call but the ringers gets in silent mode automatically but when i pick d call i am unable to hear anything from the other end.
and the same thing happened when i used to make a call on the other side , phone gets connected but wat i say is nt audible to other end and vice versa.
Please sort out these problem asap.
Contact me:
Ritesh
[protected]