unable to deregister a Pakistani Mobile number from imessages if you don't have access to the phone

Hello kashif245,

Please be sure to review all of the information outlined in the link you came from, which outlines the options to deregister iMessage: Deregister iMessage on your iPhone or online

"Deregister iMessage on your iPhone



If you still have your iPhone, you can deregister iMessage with these steps:

1. If you transferred your SIM card from your iPhone to a non-Apple phone, put it back in your iPhone.
2. Make sure that you're connected to your cellular data network.
3. Tap Settings > Messages and turn off iMessage."

If you're unable to deregister iMessage using either of the options outlined in the link you came from, we'd like to get you in touch with Apple Support for further assistance. You may be able to reach Apple Support here: Contact Apple Support

Thank you!