Calling me and said court case is filed

I was using Idea post paid for last 1 year and lasy month I switched to vodafone .
I was using a plan of 649 and bill raised 1203 . I was unable to pay bill as I cant login to app after port out and due to exceed of bill amount.
Today I got a call from 96343347517 stating that a court case has been filed against me in delhi tis hazari court for non payment and he transfererd call to a person who claimed himself to be senior advocate and yelled out on me
Prior to thid i did not recieved any call or reminder to pay bill.
This is a case of defaming and disrespecting customers .
Every month they raise wrong bill or I would say they trick customer on data uses by means of tricky policies