Picked up these lightly used B12s from a Hobby Jogger last year and have not worn them once. I struggled to get my feet into them—so much, that the heel collapsed and the inner heel counter (that little cardboard/plastic piece that gives it rigidity) bent in half. In order to unbend it, I had to cut a small slit in the fabric on the inside of the heel.

You can see this in the pictures. I do not think it will impact the function of the shoe. In one pic, I have opened up the slit so you can see it. In the next, I have pressed the fabric back and you can barely notice it is there.