Apple has introduced an iMessage de-registration tool, which assists users in turning off and de-registering iMessage from their iPhone number, for instance if they are selling their iPhone or have already sold their iPhone, and wish to disassociate iMessage form this number.
The process entails entering your phone number on the website below, and then entering the verification code which is messaged to you.
Why do I need to deregister iMessage?
You might need to deregister iMessage if you have a non-Apple phone and can’t get SMS or text messages someone sends you from an iPhone.
This can happen if you used iMessage on your iPhone and then transferred your SIM card or phone number to a non-Apple phone (such as Android, Windows, or BlackBerry).
If you recently switched from using an iPhone and didn’t turn off iMessage, your number is still sending iMessages, not SMS or text.