Idea Cellular — My Idea number allotted to somebody else

I have been using my mobile number [protected] for past many years.. I had changed my handset so got new sim & wasn't using it... i inserted the sim again in other handset, it showed inactive...

recently came to know my number is allocated to some one else.

How can my number be allocated to some one else?

This number is update in all my bank accounts, demat, pan detail, aadhaar account. ...Paytm accounts...

My privacy is at risk as all the sms (Verification code, otp, urn) still goes to this number and i am fully prone to fraud as well because of exposed information.
i did not expect idea to act so irresponsible which put me at very high risk.

Kindly take this matter urgently and give me chance to re activate my number.

Thanks & Regards,
prashant bharadiya