Tata Indicom — harased for cancellation

i have been trying to cancell my post paid mob.no.[protected] since a couple of month but the customer care is reluctant to register my complain and have been raising bill and forced to pay evary time i want to cancell dispite my reapeded request. i want this connection to be cancelledwiithing immidiate effect.they have been raising the monthly rental evan after repeated request.