Bests & Worsts Reviews from Amazon

We run a tour company, so we purchased 30 helmets. Being brief--the straps don't remain tight. After 20-30 minutes, the strap is loose and a loose helmet does damage itself to the head when someone falls. Yesterday, we had a guest with a light fall. She hit her head. The inside of the helmet--the plastic mesh inside the helmet that surrounds the head, fell apart. It's not supposed to fall apart! The phone number inside the helmet is not a valid number. It is the phone number of a hardware store in Texas that knows nothing about the helmets. We tried to contact the company directly by email address. No response. We then tried to find the company's registered office. Online through a simple real estate search, their address is shown as "available to rent". I talked to an Amazon representative today. Through their excellent service, they are honoring the return even though we are beyond the return window. (We purchased the helmets prior to the start of our tour season, which just started two weeks ago.) Note, although we are a tour company, we are not a heavy user--at 1-2 tours per day, so this is not "wear and tear". The strap on a helmet used once or five times, should not be loose after 20-30 minutes. If the manufacturer or seller responds to this message saying we did not properly adjust the straps, my response in advance is that if we are a professional, licensed tour company and we can't figure out how to use the straps, how can you expect the average consumer to do so?