What can I do if part of the soda machine fell, approximately 4 feet weighing 20 pounds and hit my son’s arm?

While getting a soda, the lid from the ice machine about 20 pounds fell and hit my 7 year old in the forearm. Instant brushing and swelling. He was with my mother in law. By the time my wife and I got there, the bruise was protonate. The manager gave him a cake and toys. He said he wrote an incident report but would not provide me a copy at all. I contacted the police department to where I could prove that he was there and got hurt. I got pictures of the lid and the manager admitted that it fell and hit my son. We went to the ER being a Saturday and our doctor was out. We had to get X-rays and all.