I tweeted. Got a DM saying they were looking into it and would update me. It has been about 4 hours... called again and supposedly it is "being delivered by midnight tonight". We'll see. I'm usually pretty relaxed about this sort of thing - stuff happens, and I'm pretty sure I've had a gate-checked bag wander off before - but it was no fun trying to wrangle a grumpy 2 year old and two checked bags with no stroller.