I bought pants with period stains

Hi! On the 3rd of March I sent my sister to buy pants for me at Jenni button woodlands. I was out of town went to fetch them on the 14th I realised the pants were small. I took them back to the mall. Kelly sent me to menlyn without checking if she had the size I wanted. When I got to menlyn they discovered the pants had stains. They than contacted Kelly who was rude & told me She can't take the pants & will not refund me becuase it'll be a loss of income to her branch. I than asked her if I am suppose to suffer a loss of R900 for pants I will never be able to wear. Mind u I only wanted a bigger size. She told me she can't do anything. She took the pants and the receipt with her and didn't refund me. She was so rude to us both my sister and I were in tears. I just need this resolved. When Tumi from Menlyn phoned her she dropped the phone on me. The pants didn't even have a tag. When I asked her about the tag she. Said it was policy to remove tag. She than told me about the. 10 days policy. I told her on Saturday when I wend to her shop it was the 10th day.