Misleading, wrongly charged and refused a refund

So I laybyed these addidas sneakers which were R750 at Footgear Oxford East London,was told to pay 25% but she ended up charging me 50%(she calculated) 2/3 weeks later I came to the store to ask for a refund coz I got new sneakers (better deal), which I was told they don't do cash refund,but when I went through Footgear website this is what I found" ,ifhowever you cancel your lay buy, would like to change the shoe selected, or need extra terms to pay, we will gladly accommodate you, and we do not charge handling, cancellation fees or interest. All we ask is that you present us with the till slip, and let us know what extra period you require on your lay buy" Their many errors with ma purchase,coz she ended up giving me a wrong laybye slip when I went to ask for a refund,it was somebody's slip but again attached my proof of transaction (EFT)slip.