This is exactly what I was feeling almost two weeks ago! I'm sorry that happened to you...
I'm applying for UCLA Luskin School as well. I started my application sometime in October with all my basic information in place, thats it. All I lost during the switch the basic information and recommender contacts I could easily input over again. I was, however, given the option to import my letter of recommendations from my professors after we received that email that the new system was in place. I already had my rant, but I'm hoping that hasn't affected you meeting the Dec. 15th deadline.
UCLA is my first choice school! Excited to hear from them, not as thrilled for the waiting aspect of the application process.