You can do nothing, and that is very scary. I remember, I was playing on a lesser known gambling platform and faced similar issue (regarding roullete). When I complaint about winnings not credited, they told me that from the next time please record your session, hahaha I mean lol, now we all have to keep OBS all the time. I never faced such issues on reputed casinos here. There were issues here and there but fixed immediately after informing them.