Refusing to refund me

I went to meet a friend for supper last night at Cavendish and while waiting for her I decided to pop into Woolworths Cavendish to have a look at their sale. I then purchased a dress last night at 18:19 to be exact. Upon trying the dress on at home I noticed that it's tight, especially around the hips. So because I work in Blue Route mall I decide I will rather return it there. When I get to customer services I get told I won't be refunded because it has make up on it. I tell the lady I bought it like that and I didn't think it would be a problem because people try clothes on with make up which would mean some would be left on the merchandise. I told her I bought the dress less than 24 hours ago and I don't even wear make up. I had my invoice with me for supporting documentation. Needless to say I left without them refunding me. I'm more upset by the fact that they looked at me and judged me because I happened to be wearing a uniform which to them clearly means that I don't deserve the service and assumed that they will just get rid of me. I WANT MY MONEY BACK!!!