Hotel threw away all my stuff... and then recovered (most) of it

I'm currently on a work trip at a conference in a somewhat popular tourist destination in Greece. I booked a hotel which had a block reserved by the conference and was offered as part of registration.

Today I returned from the first day of the conference to find that all of my personal belongings had been emptied from the room.

After some back and forth with various managers, it was uncovered that the housekeeper had disposed of all my belongings. She thought I had checked out since there was no suitcase or backpack in the room. I am flabbergasted that there was no manifest or something like that for housekeepers to know which rooms were checked in, or that she didn't check if there was one.

Most of my stuff was able to be pulled from the trash without any apparent harm. I am missing about ~£70 worth of stuff, nothing really individually valuable, just stuff that adds up (a sleep mask, several pairs of socks).

I guess I don't know why I'm posting this. Has anyone ever had anything like this happen? I want the money to make up for the missing stuff. Being completely honest, I also want to check out and be refunded for my stay so I can book a different accommodation (I'm here three more nights). I missed an important conference event dealing with this incident. I feel like I can't leave the hotel an trust that my stuff will be there. What can I do?