How to remove known phone number in Apple Pay Transaction Defaults

While in Apple Wallet I went to view/update Transaction Defaults for Apple Pay. All is correct EXCEPT an unknown phone number that I have NEVER had or used. When selecting the edit option at the top right of the screen, this unknown number doesn't contain an option to delete. How do I delete it??? I had recent fraud use by a vendor that kept billing me for a subscription after I clearly used all methods to cancel the subscription. Is this how they got around the system??? I want to delete this unknown number.

[Re-Titled by Moderator]

Original Title: I updated my wallet and found an unknown phone number in my transaction defaults under the settings tab. I can't delete the number, help?