Airtel — wrong. debit to talk time balance

My airtel prepaid mobile no. Is [protected]. On 2 may i received sms having insufficient balance in my talk time account to cover international roaming rental rs.99. Till that time my talk time balance was above rs 200. I never opted for international roaming. On 14 april i purchased plan 249 with unlimited talk time and free national roaming for 28 days. I also topped up talk time balance by rs 130 to make total talk time balance above rs 200. I am on 7 sisters north east india tour and never crossed indian border. Airtel has so for not rectified mistake. My talk time balance should be restored immediately.
A. K. Kalamkar