there are three ways to solve this issue, you can ignore the promotional email, you can unsubscribe, or you can log in and change the email to the one that you rarely use, we all have disposable emails, it only proves that you are still not cured and a mere mention of gambling site will get you irritated, a person that is cured of gambling will not get agitated or irritated from this issue, based on your post you still hate Stake.com for the many loss you incurred.
He can do those methods so that he can avoid receiving notifications. But the thing is, OP don't want to do anything and he wants it that stake will be the one to do something with it. Remove his email from the receiving list of promotions so he won't be receiving it anyway.
OP stands on his ground and won't do those things through his hands. It may be understandable for some and not for the others but that's what he wants to happen.