Airtel
Not providing data usages

I have puchased Nokia-C3 on 03 oct and their was a scheme that if we purchase Nokia-C3 then Airtel will provide us the GPRS upto 6 month (2 GB per month). First month the data usages is provided to us but in the next month (05 Nov) this facility stopped, when I talked to costumer care of Airtel Mr. Pawan told me that there was a technical mistake and these data usages will be add in my account on 08 Nov and we have followed all the rules, but this have not be done. When I again talked to the costumer care, now they are refusing to do this.