aaaaaaaWhy would it be undeliverable?? Usually the post office will leave a card in your mailbox so you can pick them up or re schedule the delivery. Did you make a mistake on your address? I would stop by or call and find out if they are still there pronto! And I'd call massdrop too.
aaaaaaaI had the same issue with my Sound Blaster E5. Apparently the Issue was that it didn't have may Street number or street name in the shipping address. Check your address with Massdrop and paypal (one of my paypal adress also was missing this info and may of been the one used by Massdrop.
I contacted Massdrop and it took a few dasy but they got back to me and shipped the item again once they got it back. It took a little longer but I got my item.
Sorry for you issues, I have felt you pain.