Hi there! You gave an honest description of what happened, sorry for your problem and I understand your frustration, knowing that wasn't you who fucked up the rotary, but I also have to understand Fkirons as they don't know if your excess of lubrication was the origen of the problem or not and they have a legit excuse to talk about warranty limits, but at the same time kind of weird that they didn't have more reports of problems like you had, and give you an explanation.
Bad idea to open by yourself the machine, even if you don't touch anything inside and just open it, it's enough to be out of warranty 99% of times with whatever the item in this world.