Seems to me, looking back, that I’ve always established early on a “you scratch my back, I’ll scratch yours” dynamic with my relationships.
I love diagnosing and fixing things, and helping others, and I also love being served as the king that I am.
I always get them to serve me very early on. Cooking for me, whatever. In return I enjoy fixing her broken stuff. She sees me as a hero while giving equal value to me in other ways.
Helping to move is in a category by itself though. I would have refused too, absolutely. But I would have used more tact. Had you said, “I won’t be around that day” or similar, you wouldn’t have occasion to write this thread.
OP, as I read your threads, I get the impression that you tend to handle things in a mis-calibrated way, and then blame the technique rather than poor execution of the technique.
This was an opportunity to casually say you couldn’t do the move while still avoiding her getting annoyed. You should always be mysterious. You’re “doing something else” that day, and letting her know you won’t help her in a non-offensive yet firm way. On the day of her move she would be wondering what you’re up to while not being hurt or offended. Work the system.