Tata Docomo — They are changing me even after 1 year of disconnection

Address:	400101
Website:	www.tatadocomo.com/en-in

I had taken a connection of Tata Docomo in 2015 which I disconnected in the same year and still they are billing me till now and sending me reminders through their lawyers

Despite clarifying that I was not using the connection, replying to the mail from lawyer in 13th Feb 2016, as below

"Despite requesting discontinuation of the service so many times, Tata is charging me bill every time. Why should I pay when I am not using the number anymore and have already communicated the same to company representatives. Every time I ask them why they are charging me for no service, they ask me to go to Nagpur. I stay in mumbai, do you think it is feasible to go to nagpur, spending thousands just to inquire about few hundreds? Anyways, I have paid whatever Amount was remaining. Its useless and waste of my money but I don't want any more reminders. So, please ask the company to close this manner now atleast. I am not using the sim and I do not even have the sim with me anymore. Will you please do me this favour and stop charging me for a disconnected SIM?"

I am still getting billed and getting reminder every month.

What kind of a company is this that would bill the customer even after leaving their services. Do we have to pay for the exit like forever in our life?