Airtel — worst customer support

I have been trying to explain how i am unable to pay the postpaid bills and even after replies from 10 different people, i haven't heard one solution that makes sense. I mention that i am out of the country and i have been suggested to walk to the nearest airtel store! If there was one, i would have gladly gone instead of expecting rubbish responses. I clearly asked them to enable otp on registered mail because i wouldn't get on sms as there is no airtel service in my city, the response says, "we have enabled international roaming". No! I still dont get network! All i need is otp on the registered mail so i can pay the bills. This has been so horrible experience as the bills just kept adding up for no reason.