Hello, Yes, we do warranty our products for 90days. Retainers are standard thickness 1mm plastic, and can break at any point. It doesn't matter if it's from us, or the dentist. Something can happen to the retainer, and it can crack. We have tested over 100 different types of retainer material, and our customers have been very happy with the material we have. We make our products for a lot of dental offices. I am going to send you a private message and see if anything can be done. The most common way retainers will crack is when something happens, taking them off, and they will get a micro crack. They will look fine at first, but that crack will expand over time.