my son who is 7 was playing out side with my neighbors kids, when the boys switched bikes. My son had never been on a bike with brakes on the paddles. He was not able to stop the bike and ended up hitting my neighbors mom's truck. Making a small dent in the back end. upon closer inspection of the bike i find that the chain of the bike is very rusted and the front brakes did not work as my son had been told that only the front ones did work. Now my neighbors mom says that I am responsible for her $500 deductible. Am I responsible for it when the bike was not in proper working order?