I had an order of three things that were back-ordered until July 1st as well. I have been living in Germany, so it was supposed to be mailed to my APO. Well, last week, we found out that we would be leaving Germany mid-July for good, so I needed to find out about the order. I was told that they were still waiting on part of the order, but they thought maybe it would go out this past week. They then did a tracking number right away, but it is still showing only "Billing Information Received" like yours.
Anyway, I am guessing that they started putting together their UPS labels in anticipation of the shipments of backorders (which they can do because I'm sure they know how much each bag and box weighs), but haven't gotten all packages actually put together.
Their Customer Service is usually good about finding out what is going on with your specific order. If you're really curious, I would just give them a call or email.