Any bipolar/borderline tutors lose clients for reacting angrily?

I had been tutoring a student for two years now. First met through a third-party service, then just 1-on-1. Her performance on the test (LSAT) has significantly improved over the years. I sensed things were coming to an end as she noted how she has to pay me for the next batch of hours.

Anyways, she recently cancelled class like 15 minutes before the session was to begin and I blew up at her via emails. I should have played it cool until the next batch of payment but I just couldn't hold it this time (she had been cancelling last-minute unexpectedly more frequently in recent times).

I told her that we should set up a 24-hour cancellation policy or something similar (we previously didn't have a need for it in the past two years) and she agreed to it. But she didn't like the aggressive tone in some of my emails and cancelled further tutoring. I'm a little shaken as I considered her a dependable colleague until now. She most likely knew that last-minute cancellations would rile me up as I have to wake up in the middle of the night for the tutoring (I live half-way across the globe).

I'm wondering if this was her way of making me end the tutoring relationship (by deliberately getting me riled up). Can one or two angry emails regarding last-minute cancellations for non-emergency reasons really end what was a productive two-year tutoring?