Mike, I can confirm that if you turn off auto-refill, you get faxes.
Do you have a dedicated fax line (separate from Updox)?
If so, you can convert incoming faxes on that line to emails which are then imported to Updox. There is no charge for emails to Updox.
We have been doing this for years; it makes all faxes to us free (though you must have the line to get the faxes). This has saved us plenty over the years.
We never turned on refill-notification. I see the fax request in Updox, use eRx to fill it (when I want to) and trash it in Updox when I do not.