AITA for refusing to pay a $1,500 bill due to the company putting my child at risk?

My son was in the hospital in June due to an issue related to his heart condition. His condition was so bad that they had to put a balloon pump in his heart (something his cardiologist has refused to do in the past, but this was an emergency) to stabilize him.<br><br>He finally got out the hospital and his cardiologist put him on several new medications to help stabilize him and keep him from relapsing. He was exhausted much of the time, so I hired a company to get our downstairs apartment (we live in a tri-level) ready for him to sleep there (easier access to the bathroom, no stairs). The company was to scrape the popcorn ceiling, paint it, scrape the walls, paint it, put a new floor in, fix the skylights, etc. This would have his bed in the living room, but that was just temporary until his condition improved and he could get back to his room.<br><br>The company was paid $4,600 to do the work. <br><br>He was doing well, so in the beginning of August (he was in the hospital in June) I take the skylights out myself to clean them and to have them ready for the company to get a good seal on them. <br><br>The company was scheduled for a week from that day, so on the day before (I am going out of the house for 10 minutes because the neighbors are having a noodle party) I took the skylights downstairs, put them on the floor, and left a note pointing out where they were, and a note saying that I was going to be gone for a few minutes and if they need anything text me. <br><br>I get back home, and there is water all over the floor. The bedrooms were flooded, and there was a roof leak. <br><br>It turns out that the company had removed part of the ceiling and didn't cover it. It had rained that day and there was roof damage due to that. When I had called asking what had happened, the woman from the company was weirdly calm and just said "it rained and the roof leaked so water got everywhere." Like that was it, no big deal.<br><br>I was out of the house for 10 minutes (10 minutes!) and the company managed to cause thousands of dollars in roof damage by doing something they were supposed to do anyway (cover the ceiling if they opened it up).<br><br>We had to call a different company that handles water damage to come in and dry out the area. They charged us $3,000 for the work and told me to contact the original company to get reimbursed.<br><br>I refused to pay the $1,500 bill that was due for the company. They refused to pay for the water damage and insisted it was an "Act of God", and are now threatening to sue me for what they are owed.<br><br>AITA?