Our data is currently being collected without our permission and sold to advertisers. If you have ever searched on your smartphone or browser for information about gambling, you will constantly receive ads with similar content. That is why it is very important if you have decided to get rid of your gambling addiction not to use your old accounts and it is better to give up the internet completely for some time.
I often get ads in my email or phone number even though I have never used my email or mobile number for gambling. If ever, I would use it at a trusted casino. Perhaps the data was obtained from elsewhere so the casinos could easily contact other people to join the casino. But maybe we can at least change our cell phone number or at least we have another cell phone number that we don't share with people we don't know.
It's true that for those who want to stay away from gambling even if they don't want to play, email or phone numbers used in gambling can play an important role get back again of that particular gamblers. Whenever I wanted to take a break from gambling, various offers started coming on my mobile by notification and then I continued gambling again.