Thanks for the reply, Helen.
That didn't however answer my questions and I could find no phone number to call Airbnb as you suggest.
I was intending to use the entire amount and more, just not in the first reservation I was making......just circumstances. The first was for only ~$50 at one location, followed by about $$350 at a second.
Because I didn't know what would happen with the balance after the first $50 usage (forfeit balance, be able to use balance, or what), I just cancelled for a refund and forfeited their$29 incentive. C'est la vie!
Would be nice if they were more thorough or had a way to clarify questions like this that come up. Just a bit frustrating. I'm sure they don't really care with the volume they have, as can be seen by some of the postings I've read here.