Winny1,
I don’t think anyone needs the store owners permission to accurately describe a product being sold.
Wolf,
In case it wasn’t obvious where I stand here, I think that besides having done the right thing (which you already “admitted” to), you owe nothing to the owner, even as a “lifnim m’shuras hadin”.
Giving the owner money, I think, would not be “tzedakah” as ItsJustMyOpinion (the English version of my screen name) suggested, rather, a present.
Had your information about the cones containing gluten been inaccurate, you might have a shaila.