You can also use Askgamblers or LCB to submit an official complaint. This way Askgamblers acts as the referee so to speak. I prefer askgamblers as they are your best success at a fair case. I have personally won every outcome on askgamblers
Back in 2012, I was scammed of 1500 euros winnings on CelticCasino, another rogue casino that has now closed, and that was rated as excellent on AskGamblers (I made a 100 euros deposit without taking any bonus). I went to askgamblers and they did not help, saying (really) that sometimes a bet was the double of a previous bet, which was against their terms and so they had the right to not pay, and got nothing back. That was the first time I got scammed by a casino, and last time (because I vet them before), until now. I do not trust AskGamblers personally.