Airtel Pre - Paid — Booster cheating

Sir,
I was using a Rs119/= booster for three months which gave me the benefit of 30p/min to Airtel mobiles and 50p/min to other mobiles and local sms at free of cost. These benefits are for three months and this booster doesnt include any talktime. I recharged with this booster just last month. Today I recieved an alert saying if I use Rs64 booster I will be charged 1p/sec for Airtel and 1.2p/sec for other phones. There was not any "conditions apply" intimation or anything regarding sms or the previous boosters.
Now I am charged 50p for sms and my previous booster was cancelled. Now I am at loss. There was no intimation regarding the cancellation of previous boosters. They announce every new scheme daily, there is no transparency in their schemes. When I complained to their customer care, they were not bothered to clarify clearly. They are not ready to show transparency in their schemes. It is total cheating. Customers are taken for granted. Had I known if the previous booster will be cancelled or I will be charged much for even a sms to Airtel, I would not have gone for this booster option.
I am at loss. Kindly ask them to explain their schemes and boosters clearly hereafter. They refused to cancel and refund the money. Why cant they cancel the booster and refund my money? It is totally unacceptable.
Yours truly,
Anuradha