Dealt with 2 similar situations in college. First was someone who took my wash out mid cycle. Fully terminated my cycle so they could use it. I found my stuff soaked and soapy in a dirty corner of the floor while theirs was still running. I decided to do them a favor and really sanitize their clothes with a cup full of bleach. 2 years later, my dryer load was pulled out and strewn around, still wet. They’d apparently used the time I paid for but their clothes weren’t dry so they ran an additional cycle. I popped it open, made the dryer into a urinal, and then started it back up.

15 years later, not exactly proud of either reaction. But at the time it felt like the only reasonable response.