How to pass the endless verifying status on iMessage or FaceTime activation when phone number is wrong?

I assume you changed phones/data plans and restored your iPhone from backup?

The only time I encountered quite important problems with my iPhone's setup was when I made a backup (in iTunes) sold my iPhone (3G) flew to a new country bought a new iPhone (4) with a new provider and setup the new iPhone by restoring restoring from backup. From that point my network settings went bad and I experienced numerous issues (visual voicemail, FaceTime and internet access were not working properly or at all).

To solve the problem I had to restore the iPhone and then setup the iPhone as a new iPhone. It was the only thing that worked for me. You could try that.

This is quite a common problem that can be solved by turning off and on iMessages. You may want to wait a little bit between these operations.