It is a defect or poor workmanship..the inside of the shoe has a huge ridge on it that hurts my feet...!    The shoe appears to be well made and fit reasonably well, until I walked around inside my house for a while, when I started to walk in them and felt my heel was slipping up and down in the heel of the shoe.  And the upper instep is either defective or poorly constructed. As others reported, So I tried to return the shoes, but Shoe Mill does not provide a prepaid shipping label. If I place an order via Amazon with shipping included how can I be expected to pay for return shipping  (UPS quoted   $18)  when the product is horribly made and extremely uncomfortable.  The shoes I received fit ok, but the design/workmanship is not acceptable on the interior of the shoe  (or perhaps my shoes are just defective, either way, I want a prepaid return label.   When I think I am dealing with Amazon and then have to deal with some back woods merchant   (the shoe mill)  that only want to rip you off , it is unacceptable.