I bought a pair of Running Shoes through MyRunway, paid for what they advertised, they sent me a confirming Invoice and then sent me the wrong coloured shoe - a woman's show in pink for a male

I bought a pair of Running Shoes through MyRunway, paid for what they advertised, they sent me a confirming Invoice and then sent me the wrong coloured shoe - a woman's show in pink for a male. I asked them to send me what i ordered and they refused instead suggesting they will give me my money back and they refuse to fulfill the contract between us. Don't use MyRunway as they are not fulfilling their obligations legally.