pressure for what? If they have already provided a deadline (and much probably this was not only related to their service) it's just time to wait.
if for all the delays that we have with casino and gambling sites (even reputable) we start creating new topics here on the forum, it ends up that we do nothing but write "to put pressure".
You are making no sense here frankly speaking. Blackjack told op that the investigation could sometimes take more than 6 freaking months and you are saying that it's ok and he should have just waited.
They should have specified a more reasonable timeline(Like a week or 2 weeks) instead. Think!
If you have complied the proof and requirements needed to run the investigation, then the only thing that you can do is just to wait. They have already provided the investigation time frame so what you will do is just to be patient. However, if it took you already longer than six months, then you better reach out to the customer support to follow-up their investigation. As far as I know, Blackjack.fun has an active support that you could reach out to.
I know that waiting for more than six months isn't easy but we have to trust the process since Blackjack.fun is also a reputable site and they will not allow their reputation to be ruined for nothing.