Until the cash-bass exchange is done I don't pin my hopes on anything be I the seller or buyer.
Don't count your chickens as they say.
I get that it's annoying and I'm the same as you Dave, I bought an electric van earlier this year which got me in a panic about the range soon after leaving the deposit, it was the first thing in my life I'd cancelled the order on, normally I'd have sucked it up but I felt even if I lost the deposit my mental health was more important.
I sold a few basses this year and one guy was practically as good as a done deal, someone else offered me the cash and I took it as the first buyer went a little quiet on me, many people would have waited a little longer for his reply and I did feel a bit bad, but, four months later he still hasn't replied!