Verizon should have warned about a backorder when I purchased my iPhone 6. I ordered overnight shipping expecting to receive it by today (2 days after purchase since I was after 4PM), but according to a phone rep it hasn't even shipped yet since it's on backorder.
I ordered a 128GB Gold iPhone 6. The Verizon order page does specify "backorder" for the 16GB or 64GB models, but when you select 128GB it changes to "Add to Cart" so I assumed the 128GB version was unaffected. Also, Verizon told me a delivery date of Oct 1 when I selected shipping options.
I think this warning needs to be clearer, and I shouldn't be charged (or have the first month begin) until it's at least shipped. In my case it's also urgent because my old phone is dead, so I won't have service until I receive the new one.