Airtel — no online recharge done by any site including airtel site also.

I can't recharge my mobile number online for almost two months now. Every time i try to recharge it comes as either recharge unsuccessful or failed. However, i am able to recharge from retail outlet mobile shop. I had approached airtel express shop twice with the issue and lodged a complaint. I even had emailed to to airtel customer care but there wasn't any prompt action. I would like to know where should i approach again with the issue. I running out of patience. I feel like throwing the airtel sim in the gutter. Once again, before i ran out of patience, i request airtel customer care through this forum to kindly resolve the issue as soon as possible.