Do you have a production number? To me, it sounds like the dealership, not BMW. Back in 2006 I ordered a 2007 E92, and I learned the games they played. Taking orders/deposits when they don't have an allocation, shuffling them as people cancel etc., obviously this is not a regulated industry so dealers can do what they wish.
But customers imho have the right to cancel and get their deposits back when they encounter the shenanigans.
As far as the wait goes, mine was 7 wks. and this was a E92 in late 2006...