I will submit a complaint at Casino Guru too.
Unfortunately, Casino Guru doesn't take care of the sports betting related complaints.
True, its looks like they give up to handle any dispute between sports betting user's and the casino because most of the cases in the past coming from abuser (late betting, fixed match, arbitrage betting, blacklist user, etc).
And they will suggest you to reach askgambler.
But maybe they will take care of that if the OP able to provide them with a solid information and data.
Did they used to handle sportsbetting related issues? I thought they don't mediate any of it simply because it's their policy instead of they're giving up on such cases. And no, I don't think they'll make exception just because OP --or anyone else-- provide enough data. AFAIK, there are plenty of complaints with adequate information that they still drop, it's simply because they don't handle such matter.
OP, I see that BC's representative was online on 26th, I sent them a PM inviting them to revisit this thread on 9 October. There is a chance that they're simply missed my PM. If you want to, I can send them another PM, but... I can understand if the prospect to have to wait again is very much annoying for you. Let me know.