[Resolved]  Idea Cellular — Charged on data pack on prorata basis

I had idea postpaid plan of 3GB 3g data, in addition to this i had 3GB Rs 450 plan. Total i had 6GB pack.The bill cycle was from 05th to 04th.Due to relocation of job i had requested to MNP on 19th nov 16 to save roaming charges .Surprisingly after my number portability which was certainly after verification of submission of old dues on 23rd nov 16. Even though they have generated bill for Rs 1640. I have used old plan for 19 days and in these 19 days i have used around total 5.95 GB data which is lesser than my data plan of total 6 GB. For these 19 days my inrenet bill came to Rs 1078 due to prorata calculation after number portability . It is total fraud they are charging unilaterlly. My old account number is :[protected]. Please help me in this as they are charging unnecessarily.