Tata Indicom Broadband — consumer exploitation

i have availed tata indicom broadband 512 kbps unlimited internet connection(Rs1500per month fixed) since last one month.but in spite of paying advance for one month i dont get a regular reliable connection..i hav spent 500 rupees on phone talking to to tata indicom help line.still half the time i cant get an ip to my internet connection to establish a connection.after that the speed of the internet never goes beyond 40 kbps.after all this now comes the intersting fact.as i availed a connection from 25th of october and their billing date is from 1st of one month 2 1st of next month,
i got a bill for date 25th oct to 30th of oct.as i cudnot pay in due time they cut my connection.after 2 weeks i payed the sum.till two weeks my connection was disconnected.after paying the bill for paying the bill for 5 days still the internet is not working.and they are going to cut the internet again on 1st of december for advance charge of one month.Since normal people cant do anything against this.after paying the amount for full one month and 5 days i cud use it only for 10 days effectively.any suggeston regarding this is most welcome nd i will b very thankfull.f