Thanks for the fast replies! I have tried to add a photo to show where the feet are breaking, but can't seem to "get it". They are breaking in the back of the foot where the quilting guide inserts. I have another single stitch foot for my old Singer, and it has a hole in it where the quilting guide attaches. These ones have a sort of a slot instead, and the edges of the slot break out - sorry - I'll go back to Janome to check out whether this was actually their brand.

The generic walking foot that I had, the part that connected to the shank was plastic and that is what broke along with the dog feet on the bottom of the walking foot fell off. It was just poor quality and I shouldn't have wasted my money on it. I did contact the well known online store that I got it and they refunded my money. And if it hadn't been half price, it would have cost more than the Janome one that I finally purchased.