A body-positive influencer has slammed Kim Kardashian's SKIMS shapewear line after buying a size large thong that was painfully too small, explaining that she had even sized up when she had ordered it. Scroll down for video Unhappy customer: Mikayla Zazon, a 25-year-old influencer from Columbus, Ohio, tried on a constricting thong from Kim Kardashian's SKIMS line in a now-viral …