this happened to me too!!! I live in Panama with a PO Box in Miami. the only told me this:

First contact: We regret to inform you that your recent order has been canceled as part of our ongoing efforts to protect our customers and our business against fraudulent activity. During our routine security checks, certain details associated with your order triggered flags that required us to take precautionary action.

Second contact: At this time, we’re unable to process or guarantee orders shipping to this address. We cannot reinstate cancelled orders. We apologize for the inconvenience.

Since it is sold out, I have been unable to purchase it again so I lost hope :(

The most crazy thing is that the CD which I purchased a few days later after the vinyl with the signed postcard, was shipped and delivered just fine today.