I've got a problem with iMessage and FaceTime

In the iMessage settings there's the option to link it to my Apple ID and I've done it, and there should be my phone number and my email but the phone number isn't mine.

The iPhone I'm using time ago was of my dad amd there was the number I can see now, and when it became mine I changed only the Apple ID but the number didn't change.

I tryed to go to change it in settings in the telephone category and I've put both the prefix and the phone number but nothing changed.

Please, somebody help me because I need this so that I can use iMessage and FaceTime from my iPad too.