Wow!!!! She sounds like a real piece of work!
Sending her food back 3x?? That is crazy! You need to ask E if she was sick the next day. Seriously, when I was in college I worked as a hostess at a really expensive steakhouse and when there was a pain in the butt customer, I just knew what they were going to do to the food before they brought it back out! It was gross!!!

All the servers would talk about it and brag about the things they did. And this was a really, really nice restaurant!
Maybe you won't have to do anything more with them. I always thought you must be a really nice person to do things with your husbands ex.