Vodafone Idea — Change of name/identity on my sim without my consent, possible scam/fraud

I own a vodafone idea(previously "vodafone") sim which i bought by registering my own documents many years back. recently i noticed that it is showing different name as the registered user name. When i emailed them about the issue asking how they changed my name\identity without my consent their representative "priyanka pawar" wrote to me after a few days that after cross checking with the local branch she found out that my number was registered on the other persons name when it was bought. Which is not possible as my number is not bought recently vie owned it for 5+ years, i see a foul play of some sort by the people who changed it without my consent as the number is registered as my registered mobile number along with my identity in many places.

i need help suing them for breach or security and tempering with identity for purpose of fraud or a scam.
Kindly guide me.