Phone number registered to Apple ID but not this device. Number Expiring

I recently switched mobile phone providers and everything worked fine until recently when I kept getting an alert about my iMessage and FaceTime Number. The message says "This number is registered to you Apple ID, but is not associated with this phone. You can keep using the number for iMessage and FaceTime until it expires." I have 14 days left! I don’t want to select the option to remove that number from iMessage and FaceTime as this is my number.

Does anyone know how to fix this please and so that my “old” number transferred witb a PAC is then displayed on my phone? Any help would be greatly appreciated.