I've only experienced such things when buying from Italy or France. I rarely buy from dealers in either country. 10 months is extreme. 3-4 months Is "normal".
ISC is a USPS international sorting facility. Packages arrive there first before being sent into customs ... which is where your coin is likely stuck. Packages can be in customs anywhere from 1-14 days, but normally 4-7. The next stop should be a USPS sorting facility near NYC, then a few days later your local facility. However, your shipment may not even show all the tracking history. I've had coins just show up at my local USPS facility with no prior tracking info after ISC. Remember, a watched pot never boils and watched tracking never moves. Good luck!
But who can look away from USPS tracking? I think I've said before that tracking packages has practically become a second hobby for me, bordering on OCD. I've learned the routes. I know which local sorting facility moves packages to my local post office within hours and which takes several days. I know what time of day my local post office sorts into P.O. Boxes. I need help...
I rarely look at tracking (unless I'm expecting a package within a couple days). Don't fret it. It'll show up. The surprise is nice.
If you're on Android(I think there's a similar app for Apple though) look for the "Deliveries Package Tracker" app. It supports most of the major delivery services around the world and can be set to check on an interval(I use 15 minutes) and pop up an alert whenever there's an update. I put everything I order into it and set it to track both the source postal service and USPS on international packages and it cuts down my tracking anxiety significantly.
Fedex takes the fun out of all that. A couple of weeks ago I ordered a coin from a dealer in The Netherlands, shipped on Wednesday, received it the next day. I had no time to fret over it!
There is just something very different about waiting for delivery of an Ancient Coin. We ordered a new vacuum cleaner online from Amazon. It took many, many days for it to arrive. It didn’t bother me one bit - Beverly was somewhat stressed however.
I do have OCD and am checking the tracking AP about 5 times per day! I've also signed up for the usps email alert whenever the package is scanned!!!
Well Finally. After ten days the coin was released. However, no scans til this morning...here's what showed up in my email inbox today... Your item arrived at our USPS facility in OAKLAND CA DISTRIBUTION CENTER on July 14, 2018 at 2:34 am. The item is currently in transit to the destination. It may be out for delivery by 8:00 am this morning. (I live in Berkeley) Yippee!
Next scan... Your item arrived at the Post Office at 7:31 am on July 14, 2018 in BERKELEY, CA 94710. Expected delivery by 8 p.m.
The USPS forgot to scan the package when it was delivered to my house on Saturday - technically it hasn't arrived yet according to tracking, with a projected delivery day of today. But, that's wrong!
Better that way than the opposite. I've had package tracking say that the item has been delivered but it hadn't. It went to my neighbor's house. It was a new postman who delivered my mail to one or the other of my neighbors for a week until I made a large sign and attached it my front door with my house number and a rather stern message to the postman. Alls well, we're good friends now. Giving him a cash tip at Christmastime helped.