Idea Cellular — Extra charges on data pack proration

Address:	500032
Website:	ideacellular

I was using iplan 299 and i still had some 100 mb of free data left in the pack.
I had ported to airtel on april 1st and had paid off 130 rs (Which was the unbilled amount till march 31st). And now when i received the bill for the rest of the days i am getting an amount of 520 rs as charges on data pack pro-ration #. This absolutely ridiculous when i still had data left in the pack.