My freeup just quit working

I think this is what happened to me. I set my FreeUP for GV multi ring and I am unable to pick up the call on my other phone (FreeUP phone is off). Didn't realize this was what's happening. I removed it from GV multi ring until I can figure a fix for FreeUP's default behavior of sending calls directly to voicemail if phone turned off.

Thank you. You described my problem in a much better way.
I did something like this before with Sprint phones, and I guess a powered off Sprint phone will not direct the google voice to its voicemail instantly. Instead, it will let google voice keep trying, so the powered on Sprint phone will ring long enough for me to pick it up.

Thank you KentE, after you turn the call forwarding on for a phone number again do you have to verify your ownership to that phone number again?

No-- once verified, it's verified forever as long as it's listed in your GV dashboard, even if all voice & text forwarding is turned off. (Well, not quite-- I've found that if I don't use a phone with Google Voice for a number of months, it's bugs me to re-verify and threatens to quit working with that phone until I do-- but seems to keep working, anyway.)
It only takes a minute to re-direct the live phone for calling, although you do need data access for it to send the info back to Google. (A tiny bit of cellular data, or WiFi.)

If you text a lot, and need to maintain continuity of conversations, I set my 'regular' 2 phones to both receive texts via GV app. If I've carried Phone A for a week, and then switch to Phone B, it immediately downloads all the text conversations I've carried on via Phone A. It probably uses a small amount of data to do this, but doesn't seem significant.

Ditto, great tip. I added back my FreeUP phone and just unchecked the forward calls for that line. Much easier than adding/deleting lines, I guess.