I also couldn’t tell if “Excuse me” or “I am sorry” was appropriate. “Excuse me” I interpret as customers telling their waiter that their table has run out dumplings (but that only makes sense if these are typically something that gets replenished during your meal, like bread(rolls) perhaps - I suspect not though, i.e. whatever comes with your dish is what you get?). “I am sorry” I interpret as the waiter telling customers they can’t order any dishes with dumplings because the restaurant has run out of them.
Given the above, should both be acceptable, or just “I am sorry”?