AP and EAD not received after almost 2 weeks in mail

[falcon7a]

My AP and EAD were both approved on Dec 27th after a customer service rep put a referral in for them. The ND for both was Oct 12th. I still haven't received the AP or EAD yet. I did receive an email notice on Dec 29th saying that the EAD cards have been mailed.

My questions is, what could be causing the delay in USCIS mailing the EAD and AP to me? I don't think both letters could be lost in the mail at the same time. Any one know what the holdup could be about and the time I need to wait before I can expect the AP and EAD?

Please let me know, I've had to change my travel plans 3 times due to the delay in the AP, I'm getting desperate and am thinking of leaving the country for good if the AP doesn't arrive in the next week.