TATA Indicom Photon Plus — Wrong Billing

I applied for a Tata Indicom Photon Plus Internet conection in Jun 2009. I opted for a data based plan called Tata Photon Plus Lite which offers .5 Gb data for a monthly payment of Rs 500/- and Rs 2/- per Mb thereafter. The company has wrongly initiated my connection as a time based plan offering 1800 mins of Internet usage on a plan called Tata Photon daily 60 which offers 60 mins of Internet ua=sage daily for a monthly rental of Rs 500/- per month. I was intimated about this 2-3 days after my connection was started, and the customer care executive was told to correct it. but the change was NOT done. I was told my billing cycle would be from 13th of the month to 12 th of the next month, bill generated on 15th of the monthn bill delivered to me by 18th of the month and thereafter I would have till 1st of the next month to clear my bills.
I have NOT recieved any bill from the company either by post or by e-mail though the request for the same was specifically given. Now my connection has been terminated by the company on the pretext o[censored]sage in excess of my authorised credit limit of Rs 1500/-. The company has billed me as per time and not as per data which is WRONG. I opted for a data based plane whereas they have billed me as per a time based plane wrongly initiated by them. The time based plan charges Rs 500/- per month for 1 hour daily and Rs 1/- per minute thereafter. My usage as per the data plan has been 246 Mb as against the authorised .5 Gb ( 512 Mb) for Rs 500/-per month.
Despite contacting the head office too, and giving a request to send the bill by e-mail, if not by post, and to rectify my wrongly generated bill in addition to re statring my internet connection, NO ACTION HAS BEEN TAKEN BY THE COMPANY.