Use another phone to call the store. I would be a on killing spree full of rage if I had to drive 8 hours and there is no phone available for me but then I wouldn't drive for 8 hours just to get a phone a few weeks early. :/
Well since I would be driving tomorrow and the reservation was accidentally for tonight, I am obviously not going to drive unless I talk to the store and receive absolute confirmation I will be able to pick it up tomorrow (which I doubt).