On the single property page the phone number displayed in the sidebar is a User Phone Number

You can change it in the user settings. There are 2 ways to customize it

1) Visit /wp-admin/ >> Users >> Edit

Please change it here:

Scroll down and click "Update User"

The other way how you can do it:

Please login as a user and visit your /panel/ page. You can click "Edit profile" menu link and change the number

Please click "Update profile" button