So if I drop by Best Buy or one of the idevicechecker vendors they can take care of cancelling the online order or do I have to do that first?
That is the tricky part. Best Buy will NOT do it for you. So you would have to IMO go to best buy and see sight on that they have what you want. Then after seeing with your own eyes the phone tell them wait a few minutes and hold it. Then call sprint and tell them cancel my order and restore my upgrade now. Tell sprint look i waited you failed to send me a phone i pre ordered and i am standing in a best buy and they have them. I would not be nasty but i would be firm. Tell them you want the phone and DO IT NOW. Once they do then buy the phone you want