Thanks Sabine !

I posted the question also on ebay Germanys help foums, and
the conclusion so far is this:
Any goods BOUGHT in the EU can also be freely SOLD in the EU without any restrictions.
Under German law Im also only bound to the contract I agree to with the shop I buy the goods from.
And because I bought my copy from Amazon Germany and not CuriousLabs directly, they can write whatever they wish into their EULA. LOL !
Teaming up to restrict sales also might be against German anti-trust laws.

ANYWAY, of course ebay CAN cancel any and each auction for whatever reason they can dream up, and so untill someone drags CoriousLabs and ebay in front of a judge to sue them they CAN effectively circumvent customers rights and there is not much one can do to stop them.

Brave new corporate world. :-(

stahlratte