Bharat Sanchar Nigam [BSNL] — poor 3g signal in my area

Address:

641004

Thirumagal nagar, peelamedu pudur, coimbatore 641004.
For the past one week signal is very poor only 2g, that too on and off several times. Rarely 3g signal received in poor condition on top of the three storey building. I have unlimited plan of 3gb per day. Hardly i can use only 30 mb per day because of poor reception. This is highly annoying. There is no customer care executive option when i dial 1503. I dont know where to launch a complaint in bsnl except this forum.
Very sad.