Sometimes if your restaurant gets and glitch, you just may never get served. You can click on your table and give it up, then chose a different table by clicking on it ask to be seated there, that may work, and save your eating out plans.
Also what I have done is add the Luxury party stuff pack, Banquet table or
Banquetia table, click on that full it with food. Others in the restaurant that's waiting and hungry will also get up and get a plate of food. It's a punch bowl add-on.
You can even take the leftovers home by putting the food in your inventory and adding it to your fridge, and not cook for a few days.