Dissiponted customer

Hey good day , on the 17 August 2019 I went to Jet in Atlantis and bought myself a skirt for church the next day . I came home and found out that the skirt doesn't fit at all.As the week pass by I decide to exchange the skirt ,thats the Friday on the 23 August 2019 .On my way to the cashier Danielle Jacobs , I ask her can I exchange the skirt into a bigger size , and I have the slip by the way , she looked at it , went to her manager, came back with the manager and the manager told me that they couldn't exchange it because my skirt is dirty and there's nothing they can do about it I told her that I didn't even wear the skirt I just fit it on and when I realise it didn't fit I put it back in the bag so whenever I have time I would exchange it. I was so upset and it's not the first time I mean to get such a service from Jet the store that I love the most I will never ever shop at Jet in Atlantis again I felt embarrass . What am I suppose to do with something that's not fitting me and that I love so much . I really don't like complain about stuff but this , this in unacceptable . The cashier had a bad attitude towards me . I'm very disappointed . It feels like I no longer want to exchange I want my money back I rather go shop where I be valued as a customer and treated well .