UPDATE:
Went to the shops this morning and when I came back I saw him and some other dirty fucker on the stairs. I completely lost it. Screamed at him and told him if he didnt give me the key I was gonna take his stuff to the garden and set it on fire. I managed to restrain myself and not hit him, they left. I called the locksmith and got the lock changed. Now I need to get the money of him for the lock plus I need to get someone to clean up the shit. Its till there