bad custome service

Hi could you kindly assist me. I bought a coat at jenni button gateway paid R1900 for it. I later wanted the matching pants to complete the look. I sent my sister to Jennie button woodlands mall. She bought the pants on the 3rd of March. I went to fetch them on Saturday the 1st think I noticed they were small. I went to woodlands mall to. Exchange them for a bigger size. Kelly remembered my sister. She sent me to Menly without checking if she had a 32 in her shop. When I got to Menlyn they had already closed. I went back the following day to Menly. Tumi saw the stains on the pants and phoned Kelly in woodlands who was so rude and told her that she won't exchange the pants and dropped the phone in my ear. I drove to woodlands mall. She told us She will not exchange the pants because she can't resell them. Had she checked the pants before giving them to my sister I wouldn't be caught up in this. She didn't even check them when I returned them. All I want are pants a size bigger. Those pants can't even go up my legs. All I received were rude comments from Kelly. She took the stained pants and the receipt with her. Could you kindly resolve this for me.