My first post on this forum, I just signed up here, because I have some experience with shipping iPhones worldwide.
USPS Customs number (both Priority Mail and EMS Express Mail) ARE trackable outside of USA.
Here is a perfect example Express Mail success: EC502462653US
Here is an example of failure (like yours): EC502365665US
USPS has worked like clockwork for me to many countries (Vietnam, China, Germany, UK, Australia, New Zealand, etc) however, I have had a few recent issues with Russia.
I have a buyer in Russia that buys 5-6 iPhones per month from me. I have shipped all to him via USPS EMS (Express) service, insured. About 12 packages have arrived just fine over the past 2 months, however a few have gone missing after "International Dispatch" (failure example above)
Now I have 2 insurance claims with USPS to deal with (1 filed about 2 weeks ago and the other just a few days ago). I have read here your problems, and on the other ShipItTo website other people's problems with insurance claims.
My issue is this: In our cases, the phones never actually even entered Russia according to the scans, so they were not "lost" in Russia, but on the way to Russia. Prohibited items or not, how can USPS deny our claims if they never even got scanned into the receiving country?
Of course the question arises about the labeling marking the actual value of the item, but I ALWAYS mark the full value of the items, for insurance purposes such as this. I have always marked the contents as "used phones" and even now I will indicate the IMEI #'s on the customs form item description to maybe put some fear into whoever would look to snatch the phones.
As an addition, I will now always be using only Priority Mail to Russia, not Express. They go through different delivery routes once they enter the country, and Express items can be more easily singled out, or generally would contain items of higher value.
Please keep us posted on your progress with your appeal, as I feel I may have to deal with the same BS in the near future.
Also, I couldn't find it just by scanning quickly the whole thread again: did you use Express or Priority?
-Nick