@Mardi15
Yes...Airbnb started removing the guest phone number from reservations last year some time I believe. We started adding the guest phone number to the reservation as a note when they book. That note stays with the reservation detail even after the guest checks out (you can still add notes to reservations with the new release, just not open nights or blocked nights).
Many of my Host clients also keep a spreadsheet in Excel and add every reservation to it and breakdown all the taxes as well. They also include the guest name and phone number on the spreadsheet.
The workaround to the notes problem is to turn on Professional Hosting Tools and use the multicalendar to add your notes. These notes are also still viewable after a date has passed on the multicalendar. The multicalendar is only accessible on a desktop/laptop, not the App unfortunately. You can click on a date and view the note in the right panel, or hover over the date to see the note:



