Additional Charges in Bill

Location/place: Pune

Name of company/service: Idea Cellular Post Paid Plan

Even when I have raised no request for activation of internet package or change of post paid plan, all of a sudden the company makes some changes in the plan and levies additional charges in the bill. I have call the customer care every time I have an issue with the plan and have to pay extra everytime I talk to the customer care executive. This has happened to me for atleast 3 times now.