This shoe is very cute and the back heel has a little metal look that is really clever.  I want to love this shoe, and have had very good luck with my Amazon shoe orders and with Nine West products in general until now.  I will not send back, but these will probably not be my go-to black flat.  Another reviewer had a similar experience with the back rubbing and suggested an insert,  I these on right out of the box as soon as I got home from work at 5:30.  By 8:30, my feet hurt and the skin on the back of my lower ankle is raw.  For the price, I expected more.  I feel like these are a full size too big - both too long and a bit too wide.  They are very cute so I might try the smaller size in the store if I can find them.  I  am disappointed.