How do I de-register a phone number from the Messages app
My phone has a registered number I'm not familiar with. It is a Philippine number and I was recently living in the Philippines so I believe in may be a number from one of the internet routers we used. The routers have a sim card. Anyway, I tried to deregister online selecting the option of not having the phone. The problem is when I enter the phone number some red text appears saying the number is invalid. I put in the +63 country code and type the number just as it appears on my phone, but I'm being told it is an invalid number. If it is invalid how can it be on my phone and how can I deregister the number?
[Re-Titled by Moderator]
iPhone 11 Pro