There are two coincidences here, one with the email address, and another with the cell phone number. The amount and type of spam received is also connected to the activity for which the number and address were disclosed.
It seems unlikely that all three events were down to chance, and can be written off as coincidence.
Even if the "rogue employee" excuse is deployed, it is STILL going to be damning for the casino, who are supposed to ensure that individual employees are not given the opportunity to steal information from the player database.
You will have to think of anyone else who could have received this same information recently, or intercepted it.
You should look into whether gaining access to your emails could have allowed this information to have been stolen, even by a rogue employee of your email provider.
The website you found features TWO distinct groups, and does not appear to favour one over the other. One is in the accredited section, but the other is in the pit, and is thought to be a failing business on the verge of disappearing with players' money.
The website owner is promoting this failing group as though it had equal standing to the accredited one, which is an indication that the rankings are probably random, and the choices are about making money without regard to the safety of players' funds.
Club World should at least look into terminating it's affiliate contract with this website as it creates a connection in the players' mind between these two groups, and when the inevitable failure of Rushmore takes place, those players who saw such website content are going to lose confidence in Club World too. Club World may then face having to clear up a PR mess caused by the impression that both groups are equally "highly regarded".
If the information IS being leaked as a direct result of it being supplied to the casino, then EVERY new player is at risk of having a spam bombardment that spuriously connects the two groups.
Given recent revelations, it would seem to be in Rushmore's interest for it to be advertised alongside Club World, and given the other tactics they have used recently, which got their iGaming rep banned from this forum and the group being "double rogued", I would suspect that Rushmore themselves are somehow involved in this, with them actively seeking stolen player data from the Club World database among others, and by generating this demand, have inspired others to actively seek ways of stealing this information and selling it on for profit.
Did Rushmore EVER have this same email address and cell number, even if this was from years ago when they were accredited?