Tata Docomo — Illegal generation of bills

I have used photon services till february 2015. i have cleared all my bills and opted for disconnection. several emails came showing the disconnection status but still bills are generated till now(dec 2015). i have not used photon services after february and there is absolutely no data usage after february but still illegal and unethical bills are being generated stating different amount of bills in each months. sometimes it asks to pay R.s. 1000 and after two months they ask to pay R.s. 2000 and now they are asking to pay R.s. 1600 which is totally nonsense. this is very stupid and embarassing fact from a reputed brand company.i surfed the internet only to find out that there are hundreds of similar bill complaints are there from users against tata docomo service especially on grahakseva.com and this site too. several calls are coming and asking me to pay the bill which is completely unethical and illogical since i have not used services after february and still for 9 months they are just embarassing. this is total nonsense from docomo. i want to stop it. i have several emails and messages which clearly state that my services has been disconnected. stil there is this problem of regenration of bills.