As I said elsewhere, you did give your email, you just don't realize it. Probably at a different business using the same payment processor.

If you ever said yes to opt in even once at once store, even by mistake, or an unscrupulous or lazy store employee ticked the box for you when they swung it back around, it gave permission for all of them.

That said there is a way to tell square to fuck off and disallow it, but I don't remember what because I did it like 3 years ago.