generate too much bill without knowing that i have unlimited plan with 750, but it’s charge 1700 and also disconnect my internet services.

Location/place: chennai

Name of company/service: tata photon

i purchased one tata photon plus with corp plan having two months free billing charge and 750 rupee with unlimited plan, but it was charging from april months, after too much complaining, they carry my internet services but, in july first week they generate 1770 rupee bill and disconnect my internet services, due to which i fail to fill online form and also due to late booking of air ticket, it’s cost me too much money.
from first week of july i called customer care representative around 15 times but they unable to give actual information and start the internet service again.After that i used company office internet and register in tata photon plus website then i check the total bill and everythings, i totally shocked to see the bill, then again i called and registered complain but again they unable to fix my fix as soon as possible, after totally frustating with this scenario, i m going to register complain against company to you.
so please help me as soon as possible.