iMessage not activating phone number on iPhone

I want my iMessage to activate my phone number back , it’s working before not until this morning

[Re-Titled by Moderator]

Original Title: My phone number is not yet activated and I really need it to work with my phone using iMessage back. , it is working with the phone before until I remove my sim and for the past 6 days now it’s not working now pls I want it to work