This is the cons of having a multiple account issue in an online casino. You can’t prove that you really don’t even if you submit ID or other form of KYC when they have proof of connection such as same IP address. The funny part is they ask for the documents then later on doesn’t believe that you are using fake ID of someone to undergo KYC for you.
It’s very hard to solve issue about multiple account and I never saw an issue related to this that resolved properly because casino will just sent the proof on AG then leave the conversation and ignore everything since they think that they do already their part. Sadly no one can verify this here if you are telling the truth or not. But one thing is for that as long as many players is still satisfied with Stake services, I doubt your will gonna be a big deal to everyone.
Multiple accounts has absolutely no upside at all, it's just a wrong move and should not be done, there is really no way around it, it is simply not what you should be doing at all. I understand that it may feel like it is actually a decent idea, but it is really not and should not be all that important at all. I personally believe that the best thing to do in this case would be looking for a way out, and unfortunately that is not going to be that easy. If you had it even once, then after many years then it can be unearthed.
So, if you ever used more than one account at any casino, just withdraw your money and go find another casino and have only one account there, even if you drop back to one account, it may cause you trouble at the same place.