Worst service ever received

I bought a lot of sportswear last week and when i went home realised that 3 of the items bought was labelled one size but the clothing inside said another size. When returning it today, i was helped and then I asked for another sizeand they asked me to fetch it from thw shelves and made me stand in a long que again before being helped at a cash desk already I am frustrated for the level of service. When coming to front I had taken another size of the pants and shirt but they didnt have a size of other item so I needed to be refunded for that. I came to desk and saw that they havent refunded me correctly they then said but when i bought the clothing it was on promotion buy two and save , i bought 4 last week but because just swopping it out now I had lost he promotion because the promotion was only for when I bought it last week. To me this is absolute *******! Im not upset about saving 30rand to me its about the fact that their clothes are labelled wrong (3 items in one shopping bag is bad)and then it becomes the clients problem and the attitude received from her behind the till after i complained was not on.