Not that it's right but it happens to everyone sooner or later.  I don't know who you have tried calling but some of the girls whose service level is pretty basic will schedule multiple appointments and whomever shows up first gets to see her; in part they do this because they get a lot of NCNS from guys.  Not that it makes it OK but that's the way it is.  I certainly don't see why if she has decided to not see for whatever reason she can't let you know she won't be able to make it though because it really sucks.  Best thing I can tell you is have some backup numbers handy to try when it happens.

As a provider who has had to cancel 3 appointments TOTAL in 3 years...

This really makes me feel bad.  I know, from a providers standpoint, I've had multiple NCNS's in the past 3 years but I've only had to call 3; well 2 I called to reschedule (once sick the other time I can't remember what happened) and 1 time it was poor planning as I didn't write it down.  In those cases I've offered an extremely generous offer to make it up to them (this happened just recently to a very respectable gentlemen so I felt HORRIBLE!).

Sorry for getting side tracked on my own stuff but I don't think any of my provider girlfriends have ever been a part of that type of disrespect. I always tell gents, "If for ANY REASON you'd like to reschedule or just plain cancel, call me 30 minutes beforehand and I don't even need or want an explaination."

If we could all respect that simple rule, this would be such a better hobby! Everyones time is just as important as the others whether you're coming or going to an incall or outcall, make sure you call before the person who would be doing the driving would be getting on their way to you or visa versa.  

Good thread and I think lessons can be learned on both sides here; both hobby'ers and providers

Play safe, be respectful and most importantly get a whole lotta dirty on the regular!

Hugs,
A-Net