Airtel India — get charged for free service

Address:

Gurdaspur, Punjab

Dear Sir,
I am using airtel postpaid service. My number is [protected]. I get a
new android cell phone on 3rd of September 2012. On 6th of September I
received a sms that I am getting free 133 MB of internet service for
free. On 7th of September I get sms that I have already used 97MB of
data service and on 8th 170MB. I called to customer care about this
and they have told me that I am getting 500MB of internet service for
free till 4th of October. so I deactivated that internet service for a
while that whenever I'll be in need I will use it. But Now they said
that I am getting charged for this and I have to pay 1600 Rs for this
so called FREE SERVICE.
I am feeling cheated. I never expect this thing happening in airtel
services. I was having complete trust in your company but now I feel
like a fool who get tricked.