Postpaid bill

Location/place: hyderabad/Vizag

Name of company/service: Airtel

I was using my airtel number(9849180088) since 4 years, And I have activated a GPRS package (98 rupees per month for 1GB), I have used 500MB of data and then I spoke to customer care representative (Bhavana) and requested her to increase my free data download usage to 2 GB then she said it cost’s 149 then I said to activate it but never she said that this will be calculated as pro rated,And she said this will be activated within 4 hours. So i have started downloading data and suddenly one day I have received a message saying that the unbilled amount is 12,456(Twelve Thousand four hundered fivty six) rupees I was shocked and spoke to cust. care again and Vardharaj (cust care excetive) informed me that the plan is not migrated from 1GB to 2 GB and the free usage is only 1 GB and I was been charged this amount for downloading the excess, I informed him that this was not my fault then he said to call to cust care after the bill is generated, However I contacted to Cust care again for better resolution and my call was transferred to supervisor (Hanumath) he told me that this is the unbilled amount and he told that the plan is not activated to 2GB plan, and he also told me to contact after the bill is generated finally the bill was 13000 rupees after the generation and I started receiving message and calls for bill payment, So I called to cust care again to speak to supervisor (Hanumath)
but Ali the cust representative told me that he is busy and will contact to me within 4 hours but i never received any call. So finally the collection agent contacted to me to my alternate number as my number (984918088) was disconnected then I spoke to a manager who is Ravi kumar and he told me that he will call me back after checking all information and he failed to call me and now an agent came to my residence and he told to my parents that I have to pay the bill or they will file a case and i have to attend to the court, So I request some one to help me on this issue please,

I would be thank full if some one helps me on this.

MY present contact number:: 9052180296
I’m working as a tech support in Genpact HYD i will be working in Night shifts only you can leave a message if i do not pick up the call.

Thank you.