You can only delete your phone number, if you have more than one – and you can’t delete your default phone number. You can also delete phone numbers that aren’t verified by following the same steps.
Note: Please have a look at this article (and read the last section) if you would like to change your default phone number
If you would like to delete one of your phone numbers, all you have to do is:
2) Click on ‘Settings’ in the navigation bar
3) Click on the grey pencil icon next to ‘Contact Information’ in ‘Settings’
4) Click on the Bin icon next to the number you want to delete
Note: Clicking on the Bin icon deletes your phone number immediately, if you delete your number by accident or change your mind after deleting it – please have a look at this article (and scroll down to the middle) to know how to add a phone number