Rejection of returned item

I bought three items from The Space in Brooklyn, Pretoria on 17 December 2015. I explained to the lady who was assisting me with the purchase, K****tso, that one item which was on sale was for my daughter. I asked her if I would be able to return the time should it not fit my daughter and she said there is no problem as long as I do not want the money back but only want to exchange. I asked her hwhat will happen if I can't find something that I like when I come to exchange and she said that I can keep the voucher for a later purchase but will not be given the money back. However, today when I went to the store with my daughter we were given a bad attitude by the staff at The Space telling me that I cannot exchange an item that is on special. Kgomotso was apparently on lunch. I tried explaining myself that K****tso said that I can exchange it. They total ignored me and continued with their work. I then told them that I am going to leave the item at the store which I did and that they should let me know what they decide to do. All I wanted was to exchange the item for something that fits and was no expecting my money back. I felt humiliated by the response I got from the staff.