I went to that store 3 times today because:
1) I wanted a costume and they didn't have it. They were expecting a delivery. I asked them to call me once it gets there.
2) They called me as they said they would, even if they are very busy. I went there to pick up the costume.
3) Once home, I realized the size was wrong so I left a message and finally decided to go back there. I didn't know at that time that sales were final.
We had a little discussion about the sizes as they don't make sense to me. For example, if your kid is between 5 and 7 years old, it says that you should by a medium, which is size 8-10. The company's (not Audrey's but the company that produces the costumes) labels are misleading. That size is WAY too big for a 5 year-old but may fit for a VERY tall 7 years old. They accepted to exchange it because I was there a couple hours ago and never opened the package. I really appreciated it because they have strict policy.
I totally understand why they would not take something back in other circumstances because unfortunately, some people are dishonest and would return an item that they wore during a party. So we are all paying the price for them when in some circumstances, we made a legitimate mistake. If you are that kind of person, i.e. someone who would return a costume that is used, shame on you. If you can't afford to buy a costume, just DIY. Pinterest could help you find ideas.
The employees were very nice with me and did their best to find the size I was looking for. Even if they didn't succeed (a customer misplaced it somewhere in the store), I appreciate the effort. My son didn't get The Flash but he will look awesome in the Batman costume.
Thank you for your flexibility and your help.