I am very new at this so I know any advice I give is just about worthless but here it goes.

If you have points at this casino, do you have any status? Could you go to a senior casino host? Would they at least listen?

Something I would try would be to have all your evidence that you didn't do it available with you - best if you had some sort of hard copy proof but at least something on a computer or screen that is very easy to look at and obvious to see that there is a conflict between what they say and what you know. I would then go to the casino and ask to speak to someone in management (you know casino structure better than me) but ask for someone that has some pull -like a security manager, or casino host manager. This is the most important part - you have to go to the casino and talk to people in person to make any headway. Go on a weekday - those that might be able to help you the most are likely 9-5 M-F types. I have found that many times those higher up the food chain will listen particularly if you ask in person (won't work to call or email). The key is to be super polite and don't lose your temper or act at all righteous - in fact acting apologetic will work the best as in "So sorry I had to bother you about this, I know how busy you are but I just didn't know who else to turn to for help, etc sort of BS). Just my two cents as a corporate executive.

I think going to Gaming first will only inflame the situation. Now, if you are speaking to someone at the casino and they are blowing you off (this MUST be some sort of manager you're talking to) you could politely let them know that if you don't get any further investigation that you may be forced to go to Gaming because you don't like the idea of having your name sullied for something you didn't do. Threaten them without seeming to threaten them - if it is someone in management they will listen. If it isn't really a gaming issue then going to Gaming may not help?

I don't know you at all Dan D, so sorry if this advice seems condescending I am honestly not trying to be.