Highly Dissapointed by MR Price Blue Route

I bought a dress in December and the dress costed me R220. The dress didn't fit so I wanted to return it. I went to your blue route store and very disappointed with the service and the response. I didn't have the slip. They could've gotten it from the system, but he refused. The item had the tags on and I obviously didn't wear the dress. The guy behind the counter took the dress and went to call someone and came back with a card. After a minutes, I asked him what's happening is he going to give me a gift card? He responds yes because I don't want anything else and I will only be getting R150 because the dress is now on sale and I don't have a slip. I then said but surely you should explain what is going on and not just go ahead and do your own thing. I asked if he could see the sale as I have the date and he said no because the slip was not emailed. I am disappointed because I paid 220, so why should I accept 150 back. I also didn't appreciate the service and response because had I not asked what's happening this guy's would have just gone ahead and processed without telling me what his doing. His manner and approach was that he didn't feel like handling this. Worst customer service ever!! I have been trying since Dec to put through a complaint on MR Price site and it also does not allow me to. I am so disgusted by this service, the manner and the fact that I could not get raise the matter with them. It's as if they make it difficult for you to actually put through a complaint.