Scammed?

So I am not totally thrilled with the results of the Yard Sale. I made a list of everything I took there along with how much I'd listed stuff for. On Thursday night, the store called me to remind me to pick up the stuff I had left over, so I went right over. I had about 6-7 things, mostly stickers, my Totally Cool tote, my quickcutz and a book. That's it. When I subtracted these things from what I took there, I should've made $104.50, but I store credit of only $78.50. That's a difference of 26 dollars, and I am not sure what to do. I wasn't told to expect any loss, but I know what retail is like. I know that things get taken, but $26 dollars worth, out of 100? That's a pretty big percentage.
Maybe when I go back to the store to spend some of my account money, I'll mention it and see what they say.