Annyoing people

A quick blurb to vent about people who mess with my schedule!

I'm a music/massage therapist and I see lots of people. Earlier in the summer, I nailed down my fall schedule. I have one parent who seems to want to make life difficult for me. She keeps changing things around. I nailed a time down with her and told her I needed that time, called dibs, etc. She said no problem...then she gave another therapist the time slot she had promised me. This is after she said I could see him at school during the day and then changed her mind on that.

To be fair, I don't know this lady at all. I only know our interactions. She has not been easy to work with at all. I feel like she is trying to make things difficult for me. Every time I talk about a time being convenient or what will or won't work, she gets weird. IT's like she doesn't want it to be convenient. I know that sounds ridiculous, but I really feel like this lady is yanking my chain.