Trai — invalid billing from airtel

I have been charged international data roaming charges. I have not requested airtel to activate this service during my recent trip. They activated it without my request and permission. Even while travelling, i have not used any data. I am still being charged. Airtel is not providing me details of why they activated international roaming without my request and also not providing details of what i have used the data for. I have already raised a complaint with airtel appelette team but even they are not able to provide me the details of what i have used the data for with clear details and also not telling me why they activated the roaming without informing me. Without providing me any information i have requested for, they are forcing me to pay the amount.
My airtel # is [protected]