Visit the official TAFCOP portal: https://tafcop.sancharsaathi.gov.in/
Enter your mobile number and the captcha
Request the OTP
Enter the OTP to log in
View the list of mobile numbers linked to your Aadhaar
Count the active SIMs shown on the portal
If you find an unknown number, report it on the same portal
You can also check by contacting your mobile operator with your Aadhaar details
Visit the nearest telecom service center with your Aadhaar card for verification