Airtel — change of postpaid to prepaid status without informing

Address:

Thane, Maharashtra

this is to complain about poor and indifferent service by airtel galery, sector 17, vashi, navi mumbai and also against arbitrary change in status from postpaid to prepaid without any intimation by airtel mobile
i have been using airtel mobile no. [protected] for more than 12 months. since its start the service of the vashi airtel center was callous and very poor. i have complained many times over the last months regarding following without any response or action.--
1. failure to issue receipt for rs. 300 taken by the vashi center as security deposit
2. failure to deliver the bill within time
3. change from post paid to prepaid status without any prior intimation to me.
i am disillusioned by the way a so called billion dollar company treats its customers. i would appreciate if my problems are solved through your intervention.
thanks.
hemant.