What if the bass being shipped was a rare 4002, or 60s 4001, or some other rare beast???
If you had dealt directly with FedEx, UPS, or the even the Postal Service you would have been fine.
This restriction has happened before with eBay's chosen shipping forwarder, it didn't matter what brand of bass, and this has happened before well before CITES' new regulations. it's been posted a couple times here on TB.
It is not a Ric thing, a shipping company could care less of Ric products.
So, it's an issue between eBay's shipper for some reason not wanting to export a wood instrument. If they're concerned over the material legality of the shipment, it's easier for them to refuse to do it than to tie up a full container of cargo and loose payout money if it sits on a dock missing all deadlines.
The first time I heard about ebay having an int'l shipping service made me wonder why would I get another party involved. You turn over the decision to ebay to process this.
And nearly immediately heard of a restriction by someone here on TB (again it was before CITES changes), firmed up my suspicion that it is a bad idea.
If I'm selling basses on ebay that I'm willing to sell int'l, then I state so in my ad that I will only ship by FedEx or Postal will not use ebay ship forwarding services..
Likewise, if I'm not willing to deal with int'l buyers, then I state in my ad NO INT'L purchases, which you can cancel the sale if an int'l buyer still hits the buy it now.