Disclaimer: I'm not a teacher.
There are lots of ways to express these concepts. Here are just a few:
I'm sorry to bother you, but could you please keep this space clear?
This space is for public (or communal) use; please be considerate [of others].
Someone's laundry is in the washing machine; I was wondering if it was yours. It finished two hours ago and I'd like to use the machine.
OR: Is that your laundry in the washing machine? It's been done for two hours now. Could you move it so I can use the machine?
OR: I hope you don't mind that I took your laundry out of the washing machine. I waited two hours after it finished, but I really had to get mine washed. Yours is growing mildew in that pile over there.
Sorry about that.
OR: Sorry for the trouble.