Airtel prepaid mobile office
Airtel mo RS.89 monthly validity problem

I activated the new airtel gprs scheme by dialling *567# the scheme was a Rs.89 scheme which gives 100mb usage and 2gb during night it has a validity of 1 month. I activated it on 28 nov 09, and rs.89 was deducted from my account and it worked properly but at 12am i got a msg from airtel saying the validity was over, but I was supposed to have a validity of 1 month. I cant contact customer support.when i dial 5 for gprs assistance it says.thx for calling.