@OP - it is not possible if U are sure that number was registered against your name.
Every activity performing against any MSISDN is getting logged in system against user ID of employees and franchises.
Incase - someone changed your ownership and then re-issued the SIM to someone else then it will be recorded in system.
Just visit service center and log complaint and also re-issue the SIM by providing original CNIC as you are the previous owner and it will be there in record.
If done by any franchisee - they have to pay heavy penalty.
If done by employee - he can be fired.
However, service center agent will not be able to provide the detail of user who performed the activity.