I have had a few similar experiences and they are frustrating, especially when I have dome to some effort and expense to arrange the session.

I now send and email a day or two before the session simply telling the Domme how excited I am to be seeing her at whatever date/time it is that I believe the session is scheduled. Usually I get a brief email back and then I know that the Domme and I are on the same page. I also got a few back letting me know that there was indeed some miscommunication and that we needed to reschedule. Better to know a day or two before the session and usually the miscommunication was my fault.