Fastest is the DM — @fuckem.nyc on Instagram. It goes to the people who make the clothes, not a help desk.
Rather write it out? Use the store contact form. Orders, sizing, commissions — all of it lands in the same inbox.
In person: inside KE Soles, The Forum Shops at Caesars, Las Vegas — or Xhibition, 1251 Griswold St, Detroit.