I'm so sorry you've had to go through all of that. As if this wasn't stressful enough!
I had a terrible experience at David's also. First the AC was broken - Texas in June is not a great month to have the AC not working. Plus trying on all those dresses. HOT! The lady that was helping us was never around. My mom and MOH were with me and we kept going around and looking for her to get other dresses. Finally she told us we could go pick up whatever we wanted and try them on. So we did the whole thing ourselves. I found a dress I loved, but she wasn't around to talk to her about it. Eventually we just walked out. I plan on going dress shopping again, but not there!
Good luck with the complaint! I hope they get back to you soon.