Builders Cape Gate Bad Service

I bought paint at Builders Cape Gate. When I wanted to return and exchange the paint I was told it has already been used. I know for a fact I didn't open or use it. Therefore, either the lady that checked it made a mistake and swapped the two paints around or they sold me paint that has already been opened and mixed. Even if they resolve this I will not recommend buying paint from them since they wasted a lot of my time trying to sort it out. I had to wait since there staff aren't where they are supposed to be and for them to check everything. Worst service ever.