Can I submit a review of a provider that made an apointment, complete with multiple phone calls up to within 20 min. of apointment time, but then never answered phone again or offered any explanation?

It has been a pretty standard rule on TER that only actual meetings can be reviewed (Even a cash and dash.), but not if there was no actual meeting.

Your only outlet in this case would be to post a warning to clients on your local board, and that's about it.

I just had one myself - same provider 2 days in a row - (and just in case you wonder why I'd do this to myself - it was a combination of hot pics, very very convienient location, and great pricing).  Apparently legit per others, just amateurish