Airtel Prepaid Connection Cellphone — wrong deduction of roaming charges

On my cellphone No. [protected] with prepaid lifetime incoming service from Airtel roaming charges at the rate od Rs.99 have been deducted for 4 months from credit balance in my account during visit to USA. Roaming facility was neither reqested by me and the cellphone was switched off during my entire stay USA. Airtel should refund the entire deducted amount and the local staff are not helpful at all.