Earlier I posted about looking into private companies to start sending foreign and overseas patron rewards. While they did provide faster turnaround times for their services, they also required three times the cost of shipment - and I don't want to increase pledge payments to cover that cost.
However, I did find what seemed to be the cause of overseas rewards not being received. Recently, I started printing postage at home. It's a system that's been working well for US shipments, but apparently not so great for other countries. So for now, I'll be going to the post office in person for overseas shipments, getting their help to make sure custom forms and postage are correct.
If anyone needs a copy of the shipment receipt so they can follow up with their package when it enters their country, (unfortunately, USPS shipping only follows a package until it leaves the US,) let me know and I'll be happy to provide one.
Again, thanks for your feedback and patience while figuring out this issue!