Do you happen to use your computer for other purposes, such as work from home?
Do you happen to run anything that helps automate certain things if you do? For example, Autohotkey?
Even if it’s not used expressly for game play, having such a program in memory will usually be detected by Warden (Blizzards anti-cheat system that scans your computer for such things).
Some categories will attract a permanent ban without prior warnings - particularly something like this which is considered extremely serious by Blizzard.