They also note on their website that if your roof only has 5 or fewer years in it than you should get it replaced. It sounds like OP purchased this home with the panels previously installed and if the previous owners put them on it was up to them to take that into consideration. It’s unfortunate but at the end of the day I’d blame the previous owner/maybe a home inspector if they had one for the purchase over the installer. They did what they were paid for, nothing more.