Would it have been better if the t had contacted you to explain the situation? If so, perhaps during your next session, you could talk with your t about this. What I understand that you are saying is that it is frustrating because it seems that your scheduled time isn't valued as a time that is important/costly to you.

I understand your frustration concerning scheduling during work time. In my job, it is hard to schedule time off because I have to make lesson plans and have my students question where I go during this time. Also, I have to ask off in advance and once a substitute is hired I have to take the time, cancellation or not. I have no "sick" days left, so every time I'm off, it comes out of my paycheck.

Bluemountains