Airtel — I want convert postpaid connection to prepaid connection

Address:

Mumbai City, Maharashtra, 400706

I want to switch airtel postpaid to airtel prepaid because so much bill comming in every month. So please convert the my mobile no:- [protected] and [protected] postpaid to prepaid otherwise i will switch to other service provider and when i went nearest airtel store they said no we can not do that so request you to please convert my above two numbers to prepaid.