Poor customer servise Edgars Birch Acress

On the 12/12/ 18 I went to Edgars in birch acress mall to do an exchange . The security guard refused to assist me because I did not have a receipt for the item I wanted to exchange . I explained that the short is a present for my daughter I did not get a receipt for it . The price tag is still attached and it is in good condition and I don't want money back I want a different size. she still refused . I requested to speak to a supervisor or store manager she then called a store manager who did not even bother to assist me . I realized later that this is not a company rule because I went to Edgars mall of Africa they did not refuse to assist me is just that I did not get the right size . I need hello peter to assist me to get the right size for my daughter . At Edgars birch acress they do have sizes but they are refusing to assist me .I want my daughter to wear this on Christmas day I cannot afford to buy her another short as I am not working .