Pathetic Customer Service

I bought a pair of Adidas Sam Smith size 6 from their store. I was assisted by Archie whom I made it clear that I need him to get me a size 5 and will come back for exchange before the 25th as I'm going away. I never received any feedback from them until I called him yesterday on his mobile phone. He then advised me to go to the store and ask for George. To my surprise the pair was sold and nobody knows who's responsible. I waited for days for this pair and no one wants to take responsibility of what happened to the shoes. The customer service is unbelievably pathetic and the attitude is of they don't care if you report the matter to the seniors or not. Browsing through the customers reports on this website it is clear that Sportscene customer service sucks big time. I want my correct shoe and someone must take responsibility and correct this!