Duckdice doesn't have solid clear reputation in the past though but there consistency to operate there casino until now is what makes them solid.
Reading the OP case many times including his rellies. He is claiming that his account is already KYC’ed even though he didn't complete this before which is the reason why his new KYC to prove the ownership is being rejected by Duckdice. It’s very hard to judge on this case because there is no evidence for both side for there claims. You can check his statement on this link https://bitcointalksearch.org/topic/m.61499918
But the current happening or should I call it developments does not make me surprise though, majority of casinos(business actually) all have their expiry date, it takes grace to continue to stay in business for so many years, and if that grace is gone, things like this will always arise and this entails nothing but doom, it is rather unfortunate that when going down, some this casinos always drag customer funds with them.