the retailers who sell feet are unlikely to assume any warranty liability. they will blame the manufacturer.
did you contact Janome by email?
i've tried sending email inquiries to big companies. i don't think i've ever gotten an answer.
i wonder if a letter sent by snail mail (with photos) might get results.
or a phone call.
i normally discourage consumer complaint posts but this one is a bit different.
do try to call or send a letter if you haven't already. i'm sure many of us would be interested to see what happens.