Spirit Halloween

I downloaded a coupon on line for 20% discount on a single item and head out to look for a cat in a hat costume and was looking for a small/medium size and the only size available they had was 1 medium and 1 x large. I decided to get the medium and while trying on the costume I found damaged/tears on the skirt. I asked one of the customer services assistance who's name was John and he nicely informed me the manager was taking a 10 minute break and was going to see if they could help me in any way. We were waiting for more then 20 minutes. Finally the manager agreed to give a 10% discount. While I was waiting on the line to check out I was thinking I still have to take the costume to be repair and for the repair was going to be about $10.99. I spoke to the manager who was at the register and he informed me that I was not able to use my 20% discount since he had already given me a 10% discount for the damages. So he ended up using the 20% discount in a pair of gloves that were 6.99 and it discounted $1.40 . my total amount came up to $62.00. Now my question is was that fair for me to only have 5 dollar discount for a damaged item?. After I payed and walk out the store. It came up to my mind that it would of be better to just use the %20 discount on the costume which it would save me $10.00 instead of $6.00. I went back to the store to return the items and purchase only the costume with my 20% off. The manager and the other cashier were very rude and keep on telling me to be glad they were doing that for me. I just know I would never go back to the store the customer service is so bad and the only professional and nice person was John who apologize all the time. Also some of he employees were vaping on the back but the fitting rooms that is very unprofessional.