Someone could have official terms and conditions with proof about the date. Such as for example receiving them by email or having them archived on a reliable website. I sent an email to support a while ago but I suspect they would be bothering with such a request and still waiting, unless they are exceptionally good customer service.
You must understand, though, you are asking for a document which is very unlikely someone got here in this very small part of the internet. You would even have a better shot by openly asking for this document on other places with a larger volume of gamblers, perhaps on X/Twitter or even on Reddit.
Also, anyone who sees this thread you have opened will first assume you want to have that document in your hands because you have got some litigation going on against that casino. The staff of the casino could easily claim to a judge/jury the copy you have gotten through unofficial means has been tampered with to support your claim against the casino.
In your case, it would be better just to go through the legal ways and ask your jurisdiction (your government or the government who has issued their license) to request a copy of their previous Terms of service in your behalf.
Anyways, I wish ya a happy new year eve and a pleasing night.