Tata Docomo — Looting Money !!

Some customer person called last month saying that he would change my plan from 199 plan to 350 plan for my betterment. I asked him how can I change because it was already around 17-20 June and any change in plan had to be made before. I told alright and then started using net pack for the entire month. But then only on 15th July did I get a msg that plan has been changed.Because of your customer care persons I have around 500 Rs in my bill which was charged for net (Which I would have not used if I had known there was no change of plan). Even after repeated questions, the customer care person told that this plan would surely start from June. This is highly irritating..because I wanted to change from postpaid to prepaid and instead she made me change plan and now pay extra. Isn't this your communication fault? How are you gonna repay this !