Mis Sold Dr Brandt Product

I went to Foschini on the 26 August to buy a open an account and was approached by Dershni, to cut the long story short, she mis sold to me and two weeks back she took the products back and gave me a credit for the two creams but they tablets she made me purchase was finished and she refuses to give my R400 for it, the product didn't work and she **** to me but now she is refusing to credit me for the tablet, she lies to customers to make a little commission, i also found out that she did the very same thing to another lady and i will be taking the matter further