For the one you should have already, if it is coming from a country that is using any form of tracking or customs ID, you could ask if they have a number yet. I know when I mail anything pin wise, it always has a tracking or customs number that shows I dropped it off at the local PO, so while it might lost in the ether known as post office limbo at times, the recipient will always know I did ship it and then both they and I can follow up with the local post offices to see if it can be found.
As for "No Reply", have they logged in since your last PM? If so, I would forward that to a mod. If they have been MIA, there might be something else wrong, and you might need to see if you contact them via another means.