Unnecessary balance deducted as the charge of caller tune ?

Hello, I am facing lots of problems from airtel now days. The service of airtel is very bad. I am using airtel for over 1 year and the service of airtel was very good those days but I am thinking to change my service provider due to continuously problem from airtel. Some day before I complained to the customer care of the airtel about my unnecessary balance deduction but after some days they again they again cut my balance and when I asked them why this balance deducted from my account then they reply that its caller tune charges which I don't even using. There is no caller tune service activate on my no. but they balance is still continuously deducted from my account.