These two casinos (1xbit and 1xbet) are sister companies. Both are from Russia. Also both has very bad reputation here as well as on other forums and reputable review sites. Just like what others said, I will advice you to assess them properly. Avoid playing and making your next deposits there before your decision.
Roobet, Duelbits, Rollbit, and Stake are few of those that you can play with less/no problem. Goodluck, do some background checking first too before depositing any amount.