Hathway Cable & Datacom — harassment despite cancelling the connection

I cancelled my connection in 2016 at banglore. Hathway raised a bill after i cancelled their connection. I kept getting calls from them saying you have unpaid bills and i told them that i have canceled and not used their services since then. They called again and again and i told them the same and asked them not to call again. Today (7 june 2018) i received a suspicious call from a woman (Sharma) claiming she is a lawyer from delhi saying there is pending dues else will file a case. Then she said hasn't filed the case yet and will give us 30mins to pay, else she will file the case worth rs 58000/-.

This is a dupios company, harassing innocent customers.