MBit casino guys aren't really active on this forum so its unlikely that they will see your request.
They seem to be active on twitter:
https://twitter.com/mbitcasino so try making some noise there they will have to respond eventually.
They aren't active because they have ongoing scam accusations that they're avoiding.
They know about this and are avoiding it on purpose because they used to be active on the forum before the shitstorm started. They even had a signature campaign here for a while.
They got negative trusted in 2018 and were posting after that but have not addressed the problem, so they know what's up and choose to ignore it.
i don't think the OP can resolve his problem. i am seeing that just move on from this disappointing experience from mbit. if the site will be willing to pay, they have at least responded on him. unfortunately, they are also not active in this forum, so hard to get answers also. the amount is not worth pursuing a case. a lesson learned, better play on reputable sites that you can find in the forum, with at least active thread and support.