Terrible Service!!!

I went to Sportscene Gateway mall on the 26th of August to purchase All Star (shoes) , the actual price on the box was R750 how ever when I got to the pay point the shoes scanned for R850 , I told the lady who was assisting me that the price on the box is not aligning she then called her manager and he assisted accordingly he voided the price and I was sold the shoes for R750. I had to go back on the 29th of August to change the shoe size from size 5 to size 6 , I took the EXACT SAME THING, Guess what I was told to add R100 !!!! I asked the lady for what? cos I'm doing an exchange I'm not taking anything different? She called her manager to assist with the query mind you from the original price they have now put another price on top to hide the old price (Broad day light ****). When she came she REFUSED TO DO THE EXCHANGE INSISTING THAT I ADD R100 and I did !! Now my biggest question in this whole **** is, does the consumer protection act condone what Sue (Store manager) did to me? Is this how things are done? The service that she gave me was very low I've never in my entire history of being a Sportscene client have i ever seen such disgrace . Sue needs some basic lessons of running that store or she will have to buy everything in that store on her own. Terrible Service, very unprofessional and unacceptable.