Bad experience with Jet Heidelberg Mall

I had a very bad experience with Jet Heidelberg Mall. I bought a trouser for R199 and pay and on my way out I saw another design which I took and exchange the one that I bought and they were of same price. The lady who was helping me charged me another R199 and promised that the money will be refunded immediately. This happened somewhere in July and until today I never received the refund. I made a follow up on several occasions and the attitude I was given was very bad by the same lady who made the error. I was told to submit my bank statement which I did and I was promised that the money will be refunded but until today I haven't received. The manager and the supervisor also promised and nothing happened. When I send emails they do not even respond. Every time I visit the store (Jet Heidelberg Mall) they tell me that they don't know me so I have to explain my story again and again.