Airtel — About Rs. 199 plan provided to me.

Address:

Mumbai City, Maharashtra

I have opted Rs. 199.00 CUG plan in which there is unlimited 2G Internet + 10% discount on bill an converted my prepaid number to postpaid. Now I have received this month bill(11Dec to 12 Jan) amounting to Rs. 404.99 in which Rs. 278.44 is charged only for mobile internet usage. Why this anomaly? Kindly redress my problem and issue rectified bill for the above period to enable me to pay the bill at the earliest.