Airtel Pre paid services
Booster pack not confusion

I opted for a roaming booster pack and paid Rs.42/- for the roaming booster. I also have a regular booster face value Rs74/- by which my calls to Airtel mobiles should be charged Rs.0.20 and other moile and land line at Rs.0.50. But when ever I call any number Paise 55 is being debited to my account. I want to know why.

My mobile no. 9940624469. My mail id is

V.Shunmugasundaram.