Airtel — disconnection request and service was cut but billing is going on

Address:

600018

Hello airtel

I really enjoyed the service and speed airtel provided and had to disconnect the service as i am leaving abroad for years, with proper reason and time i had initiated the disconnection request and to my sad, i am still receiving bills and calls for payment, i have made a final payment and don't want to pay anything in future as service was cut in sep 2019 itself and i have paid additional month payment also oct 2019.