U-Haul Failed to Secure My Trailer Properly and Put Me In a Dangerous Situation

I had a really bad time renting a trailer with U-Haul, and I can't suggest it to anyone. Since it was my first time using a trailer, I made sure to tell the U-Haul employee, counting on them to make sure everything was secured right. Sadly, that wasn't how it turned out. Right when I began driving, I saw a chain trailing on the road. The sound got really loud, and I had to slam on the brakes. I noticed that one of the safety chains had come off completely and was hanging down dangerously behind. As someone trying this for the first time, I really tried to sort it out, but it was super stressful and felt unsafe. I thought U-Haul would provide better service and be more focused on safety.