It is only their respond can verify your claim and innocency. A casino would not just blocked you account with them. They must have seen or noticed some unwanted movement in the account. Probably you have played game with different account with the same IP or your friend did that. Or other reasons. And as I have seen from other comments, stake does not reply to complains here in the forum and I believed they have other channels that deal with those complains and solve issue. So you can reach to them on those channels either by email, Facebook, x, from the site support or others. I wish a successful resolution.