If they didn't see you then they have no right to apprehend you. Because most stores have to follow a five step process, so that does not include all five steps, I hate crooky AP and Police, etc. I'm sorry for you predicament, at least you are lucky and do not have to go to court like me!

I know about the five steps because I have become certified in AP where I work. They have to see you actually pocket the stuff otherwise there is no proof. I know it sounds silly, but they caught you wrongly, but at this time there is no way to get out of it.

Don't do it again. If you do though, ask for proof that they know you took something first.