Airtel — not able to recharge online to my airtel prepaid mobile number since one year

Address:

Thane, Maharashtra, 400601

I have been converted my airtel post paid number to airtel prepaid number since last year. Till then i could not able to recharge my prepaid number through online. I have called multiple times during last year months to customer care to resolve this issue, but no solution from their end. Even i mailed to [protected]@airtel.in several time, but no reply from their end.
Customer care person behaves so roughly.