Got a call back today but it was a VM. I called back and left a VM of my own. No response to that. progress, but not much.
EDIT: Got a call from a gentleman at AEX who said he had already contacted the shipping department ('You're the guy who sent some emails, right?') and would follow up with them again. The next day I had a tracking number of my missing part. A+ on getting things sent out quickly, D+ on actually letting the customer know what's going on. I'm gonna take a cue from Munin and not use these guys unless I have to from now on.