[Henk]

It is wise to have an additional email account that you use for these kind of websites. When you have an iCloud or DuckDuckGo account the browser already gives you the possibility to use a generated email address, that can be disabled at any time. I always use such an email address when I visit a shop for the first time.

Also never give your real birthdate, I always use 1/1/59 which is near my real birthdate but not exactly 

I have an old email address I can't get rid of because of my provider. I get a lot of spam there so I found out that this address was gathered in a LinkedIn data breach.
If you like to check yours, visit this site: https://haveibeenpwned.com/