Tikona - charged for services not availed

I was a Tikona Digital Networks customer(User ID: **********), I had a lot of complaints with their service and their internet was terrible, so I decided to discontinue and paid my last outstanding bill and send an email asking them to disconnect the internet and stopped using the same. Still at the end of the month I got another bill for internet usage which I refused to pay since I had not used their service and had already got another internet service provider. I got a call today from a lawyer from Delhi civil court stating that Tikona Digital has filed for a case with the Delhi civil court and I had to pay ****RS or else my ID good be blacklisted for **years. I have paid this amount but is willing to file consumer court for emotional trauma and money extortion for unused service against the company.