Discusting manner in which I was humiliated

I went into Dischem to buy product for my knee after tearing the ligaments. When I got there there were several knee products available, knee support, braces and guards. I went to the pharmacist lady which on duty, I explained to her that I have just came from the doctor and was diagnosed with cross knee torn ligaments and had to get some kind of knee support. I took all 3 products with her and asked her if she perhaps knew which one I had to purchase for my injury and that price was not the issue. The ranged from R80 and R280. She started laughing at me and said there is no difference. I could not believe it. I said to her there must be a difference as the lower price is just a weak support and the higher price came with plastic support strips for maximum support. Then she laughed at me even more and said what do you want it is like buying a volkswagen or a BMW, they different cars but will still get you around. I have never been so humiliated in my life, been laughed and mocked when asking for advice. We went to click, the pharmisist chose the correct product for my injury and event fitted it on me according to size. All I can say is your staff member should be fired!