Sent the wrong shoes and are ignoring us

Hi. My friend and I have been trying to get in contact with you. You sent the wrong shoes a month ago and said that you would send the right ones and fetch the ones you had sent. Since then, you have ignored all emails, social media messages, all of our calls have gone to voicemail. We just want our money back now. I will even personally come to drop off the shoes that were incorrectly sent at your address in Rivonia provided that you give us our refund. We can prove that you sent the wrong shoes, said that you would send the right ones but haven't and that we have tried many times to contact you.