Exchange policy at Greencross Greenacres is very bad

Gudday all I bought my fiance ladies shoes at Greencross Greenacres for R899 on the 12th of July 2019 as a gift for her birthday. The she did not fit her well and she decided to exchange it for the right size and the same make after 3 weeks (7th of August 2019),since we're from Grahamstown (140km ). We could not find the receipt and since the shoe was never worn and new I didn't think it will be a problem to change the size. My fiance went to them to exchange the shoe and they refused because there was no receipt. They ask for my bank statement via email since I was not there at the time. I sent the email with the details of my purchase that day but they could not print it on their side, so then they refused to change it for the right size. I found them caring about their clients as if you can't buy someone a gift at Greencross Grenacres because shoe makes and materials are not the same and no one can guarantee to keep the slip until such time. Thank you to their bad service my fiance cannot wear the shoe and I lost R899 on a brand new shoe.