Airtel — cancellation of services [protected]

Address:

Chennai, Tamil Nadu, 600004

I am trying to deactivate the above post paid sim 4g data for the past two months. There is no option with 121, 198 or through loging in to my account. Airtel having started this exploitation of its individual clients, others will follow soon. I want to immediately cancel this service; don't mind to give up the balance data available in my account, but wish to get out of this menace once for all.