Can't speak to your issue but here was my experience:
I had to cancel on a provider here this week. I didn't want to but it was unavoidable.
There had been another date I couldn't make a couple of weeks earlier so this was my 2nd cancellation.
I offered to make it right, since she'd spent a good deal of time emailing me back and forth on both occasions.
I emailed her a gift card for an hour of her time.
She emailed me back that she would credit that against a future appointment. I think I found a special girl and one I am going to spoil if I get the chance