My question involves a roommate in the State of: Illinois
I live in a 3 bedroom flat with 3 other people. One person pays $300/month, one person pays $400/month, I pay $400/month, and our last roommate pays $100/month. the last renter used to live in the room that the person paying $300 lives in now, but had to sublease when they lost their job, and has since been sleeping in the living room. They are signed to our one-year lease, the subleaser is not. We have one month left of rent to pay before the lease is up (thank god) and the couch roommate has decided to move out. While i wouldn't expect them to pay utilities for the last month, I would expect them to pay their portion of rent, but they are angry and unwilling to pay. Even though they still have a key, have some of their belongings here, and left a cat, which i've been feeding and taking care of (they said they'll get her eventually...). What can I do to ensure that they pay their portion? While it doesn't seem like a huge amount of money, none of us can cover it, as we're all trying to survive and get by in chicago on little to nothing.
my second question is regarding damage they caused in the apartment. One night they angrily punched out a window in our front hallway. It's been broken for over a month and a half, and they have said repeatedly that they would fix it. This past weekend, they got incredibly upset with me because I had some friends over in our common space, even though they agreed earlier in the day when I asked if it'd be ok if I had friends over, that we'd be quiet and told them they could sleep in my room. The next day, I got a message online that said among a lot of rude things, that they'd be leaving. I also got a text message (which i saved) that said, "Oh, and I changed my mind about the window. since my voice is apparently mute in household decisions, I don't see how I should be liable. it's your house right? So your window to fix." I also have previous texts saved from them that said they talked to our landlady about fixing the window. I also have witnesses to her actually punching out the window. She's usually a really calm and nice person, but the last 3 months or so she's been really unpredictable and hard to live with. What actions should I take to see that they clean up their mess?
Thanks for any help. This is such a dumb situation, and I just want to get it cleaned up and dealt with in the best way possible for everyone.

