I'm so sorry. What a nightmare!
My SA mention that it should be tighten periodically for the 1st week and after that it should stay put. I made a point to check on the screws to make sure it hasn't shifted. I am on my 2nd week and I still notice loosening I am probably going to wait another week and then give my SA a call. I never had a problem with my other love with the old system.
I'm surprise you weren't able to find the 1st half that fell off....how did the 2nd half stay on that long without being attached to anything??