[Resolved]  Tata Docomo — harassing me with calls and text messages to pay bill though i've never used their service in the past

Address:

Chennai, Tamil Nadu, 600099

I'm not a docomo customer nor i have never used their service in the past. I got a post paid number from vodafone 2.5 years ago and ever since i've been getting calls and text messages asking me to pay the bill of rs. 1799 every single day or i will face legal actions. Why would i face legal actions when i've never used their service in the past. Also i've made several attempts to contact their customer support but no luck or they would not do anything to stop contacting me about the same. Please tell me if i should file a harassment case against docomo for the same if so what would be the procedure?