Hello if I changed my phone number , how come I can’t receive from new contacts since I changed my number?

Have you changed the phone number on your Apple ID and in Messages/FaceTime?

You need to change/add the number on your Apple ID. Look in the Security section when signed in online. You may have to add the new number before you can remove the old number. After the change, allow up to 24 hours for the change to sync. Before trying to make the change, sign out of Messages/FaceTime on all devices/computers.

Apple ID - Manage