Have you found anything else about the scam activity? I am not familiar with the gambling site but I do not want to conclude the gambling site as a scam. The email might be sent for the account you have created or mistaken even many people who may create an account by taking the email of others to spam or waste the time of others.
That is possible but to be safe i would not engage with an email sent from something i was not familiar with. If other people randomly found out about my email then used it to register (and fail) then i would not give them that satisfaction. Better to ignore because there is still a chance that it is indeed a scam and may just be trying to take your attention.