Has anyone who tried these shoes had the same problem with the plastic in the shoe's heel digging into their foot? I've only had these for a few days but I can't even wear these without pain now because the fucking plastic has left blisters on my achilles. It's not a sizing issue, because the rest of the shoe fits fucking perfectly. Will this go away as I break them in, is this a defect, or am I fucked? Anyone know?