Consumer Redressal

i am using reliance broadband connection along with landline phone no. 033 30270777. I have been receiving SMS regarding by un-billed usage which at present is around Rs.11,000 (un-billed usage from 24th May 2015 till date) and the connection has been de-activated for past 10 days. I spoke with customer care few days back regarding this and they said I do not have to pay any amount now and the un-billed usage is showing as Rs. 0 in their system. I received a call from Kolkata Reliance stating I need to pay the above mentioned amount before my connection is activated. I had asked for itemized bill many times because I did not usage the services as much as the bill amount shows but to no avail. They said I need to make the payment first before reliance activates the connection and then they can send us the itemized bill. They are harassing us like this without giving us the itemized statement and asking us to pay the amount first. Kindly help.