Idea pre paid sim card
No signal while in home but signal is full while in roming

My GSM hand set is Motorola c 201, the idea pre paid sim I purchased in novermer first week since then there is no signal while I am in my home town i.e. Panvel though I am getting full signal while roming Pen area. I had louged this complaint (compalint id 728099) many a times but this problem is still there... sometimes customer care executives are suggesting me to change the handset, as this sim is supporting with full signal everywhere Panvel, Pen etc if I am using my friend's Nokia Handset.

All other sim Vodafone, Airtel, BSNL, etc are responding very good signal with this Motorola Handset.

Should I change my handset?

OR

Idea can help me in this regard?

Sim no. 09702113648.