Airtel — airtel customer care failing to register my disconnection request

Address: Bangalore, Karnataka, 560030

Hello,
Airtel customer care failing to register my disconnection request and has been charged 3 months usage charges. Very poor response from customer care and no one taking responsibility and inspire of almost 15 calls, not even a single call/ complaint has been registered.
Relationship # 12609293
Number in question[protected]
My mb# [protected]