Ahhh why you don't accept customers from Germany? Am so sad, I wanted to try your website out so bad! 
sometimes it is hard to believe but nothing that we can do mate, I am with your own position also when there is a great casino that I wanted to play but they are not allowing my location to play.I think you can try contacting their support if there is something they can do for your case ? but not sure if it is allowable by any case.
and yes if you have not played in roobet then you missed once and a lifetime chance because of their greatness and providing better experiences to their players.
Roobet.com may not allow people from Germany to use their platform for reason like there are specific rules and licenses required for online gambling in Germany and Roobet.com might not meet these requirements or want to deal with the legal. Roobet.com may be concerned about taxes and fees associated with operating in Germany.
But the best thing to do is check Roobet.com's terms and conditions to understand why they might block users from Germany.