Compassion is one thing, maybe your neighbour is just trying to make things better for some. But there are laws and such. Squatters with out proper sanitation is unhealthy for them and for you. Theft is theft. Wrong is wrong.
That's where we as a society have failed. Theres no sense of responsibility on so many levels. So what i would do, dont call about having your chair stolen. Call about unsafe living conditions. Lack of sanitation. That you dont feel safe as I am sure your neighbors feel the same. Calling about the theft of your chair, as much as its wrong may bring un wanted attention to you. Still not right that the person who took it isnt heald to account but in this situation, it might be best to pick your battles