Wow man, I feel for you. That is terrible. I would try going through BMW of NA to tell them how horrible your experience was. All that wasted time is pretty uncalled for. I don't know how hard it would be though to get those 3 months back in payments.
Question though...how is the car running afterward? Besides the startup, could you ever tell? And was it only submerged 2 feet? Just wondering. Hope things get better!
2016 340i M-Sport 6-MT(on order)
2013 335is (still have)
2011.5 M3 ZCP (traded in)