[Resolved]  Airtel Prepaid — Airtel SMS plan Changed (Bitter experience with airtel prepaid service )

Hi All,
I am using Airtel prepaid connection for a long time but recently I got surprised with an unusual problem from their end . I have recharged with 53 Rs SMS pack in kolkata (Valid for local/std/ISD )and got 250 Rs sms balance for 30 days on 6th December and it was deducting from my sms balance when I was sending any ISD sms but from 13th December it stated to deduct from my main balance whenever I am sending an ISD sms . I have launched a complain to airtel on 15th December with the complain no “[protected]” and they assured me it will take atmost 17th December to solve it but on 17th when I contact them as nothing done they are telling me it will be fixed within 30th December! .Even when I asked them if you take so long time my sms validity will be over they replied they can do nothing only can forward it to concern people and they even will not extend the validity or repay the balance even in spite of their fault .
Now please tell me what action I can do from my end ?