Bad service by Luminance Sandton

I bought sneakers at Luminance Sandton under the pretense that it was size 8&half. The lady who attended me committed a mistake by give me 9&half instead of 8&half. The following day when wearing the shoe I established that the shoe was big. Because of the confusion or ignorance of European sizes I couldn’t make a determination of a wrong size there and then. Now the shop doesn’t want to exchange the shoes claiming that I have worn the shoe. I submitted to them that there was no any other way of determining whether the size was correct had it not been for wearing the shoe and feeling that it was a bigger size. Especially if you are under the impression that it’s a correct size. The only reason why I had worn it with is because of the reasonable expectation that was created that the shoe is an 8&half.