Exchange of goods

I bought shoes on the 27th November and I removed the tag because I obviosly wanted to wear that shoes then I realised the size was small and when I take it back to the store to get the right size Sphiwe told me he won't exchange them for me because I already removed the price tag. I tried to explain to him the reason why the tag was removed and I still have my slip but he just gave me bad attitude. I am very disappointed and upset at the same time. can the management please do something about this. because its not like I used those shoes they are still in good condition, its only the price tag that has been removed. I really don't deserve this type of service from him.