Disappointed

I bought a dress at pick n pay clothing carnival mall last month. It was R180, and to my surprise it had a whole. Unfortunately I couldn't go back to go change it because I was highly pregnant, so I asked a friend last week to go get a refund for me. They didnt want to, she was told that it's over 30 days she needs needs to atleast take something. So I asked her to go take a jersey for me, which was R189 to her surprise when she gets to the till she was told the dress have been reduced to R80 so she must get something for that amount. This doesn't make sense at all. 1 the slip doesn't even have a return and refund policy, if it has a refund policy I was going to make it a point that I follow the rules 2. It doesn't make sense that I bought something with R170 then when I go for exchange then I have to take something for R80. THATS A REAP OFF!!! Please help!! I can't go there myself, I just gave birth and my operation is still sore!