Unfortunately, in your case they hold the balance of power and you cannot force them to expedite the process. At this moment you do not know what the third party game provider is investigating. If you are not willing to wait because you complied with their KYC request and you feel you should have access to your account, you have options such as asking CasinoGuru and/or Askgamblers to arbitrate.
I can accept a review but in a reasonable timeframe which this is not also this is a prelive bet too if it was a live one i would understand but what on earth is taking so long