Why would your first assumption be that they were hacked - first thought: They are trying to make some $$$ by taking advantage of their user database...
I wasn't sure if the email was leaked from Betnomi or it was Betnomi. But as notblox1 said, his email was exclusively for betnomi. So, it's confirmed that either betnomi server data was leaked, they sold user emails, or they are simply trying to make money from affiliates.
Another possibility could be that they have opened another business that is forwarding those users. I did not click on the link I received from the email, so I couldn't check the platform. So can we consider that Betnomi rug pulled?