Airtel
Customer service

I requested the Airtel Customer care that I have to submit some document to my office to be eligible for the telephone expenses, from the date I became its prepaid mobile customer,

as in post paid service there is proof of the mobile services the customer uses, the same is not available for prepaid users, so I just requested the customer care to just tell me the specific date in March when I became its customer, but the customer care is as usual very unhelpful and rude.

Somebody please tell what should be done