So they just created the multi-accounting allowance to scam people? If it's considered fair use in your eyes, then there's clearly something wrong with this industry, something wrong with you protecting them. If a player plays by the rules and follows every rule and every clause of Rollbit's T&C precisely - it is Rollbit's duty to make sure that they are honored - which they were. Banning someone without a reason and no explanation at all is just bad and careless practice - a dishonest one.
Looking at this case from all angles, i must confuse that O.P is to be blame to some extent. Because in as much as multi accounting was allowed, by you creating a new account immediately after the previous was limitedd with the same IP address was kind of fishy and you playing on Rollbits intelligence, of whoch no casino will ignore such act. And if you must multi account, why can't you be smart enough by using totally different devices with a different and unique IP addresses? But instead you went about using just only 1 which have equally landed you in this mess.
But however, everybody has said everything that needed to be said in the previous comments, so what remains now is for Rollbit or its representative to come tell there own side of the story, because $10,000 is a huge sum to just let go just like that.