Speaking as a vegetarian and a fairly good cook, I don't see how matzoh ball soup could be made vegetarian, because the chicken stock and its flavor is so much a part of the dish. Can't fake it; nothing else tastes the same. Sorry. Such is life. Andrea was unreasonable, and then very unreasonable and rude, too. Nobody should insist that I make my black bean soup with a ham hock, either, because they are apparently terrified, for some reason I cannot fathom, of a meal without meat. Yes, this has happened. And that is an instance where there is, I am reliably informed, no difference at all in taste. Chicken soup? Come on! There is no substitute.
If you want gluten free, look up recipes on line or at the library. It isn't as simple as one for one substitution -- been there, done that, doesn't work. But there are cookbooks, and some of the baked goods are first choice, my new recipe, superb.