Bad attitude and Bad Service

On Monday the 24th September 2018 , I went to Woolworths Festival Mall to exchange a pair of jeans I bought on lay-bye which I fully paid it on the 21st September 2018. Manager in charge on that day denied me exchange due to the jeans that had dust on the lower part(feet) . I might have bought it with that as it might have fitted by more than one person. I also fitted it home and felt that the size was big. I did not want a money refund I only wanted a smaller size on the same jeans. She was very unhelpful and given me a bad attitude by saying she will keep it and whenever I want it I will come to the shop and collect it. Finally I left the jeans in her care as I couldn't take it with due to a wrong size. VERY BAD SERVICE I have received .