Idea Cellular — Harassment by calls and messages

I am not using Vi since 2 or 3 yrs, still Vi forcing me to pay the bill.
Last yr in mar i talked with Vi executive, I m ready to pay bill while sim card is not in use, but assure me, you will disconnect my no. permanently. With assurance of executive, we will disconnect no. permanently. I paid bill.
But still they started generating bill and harrasing me by calling and sending msgs to pay bill daily.
Pls look into matter.
Thanking you
Madhu Sharma