So let me get this straight. You don't want an account anymore. They don't let you delete your account and you violate ToS. Them banning your account is to your detriment how?
Well, if they just ban its great but I am wondering if they can ever go to court with this and sue or something. Needs lawyer advice here.
You can't stop the notifications if your account is deleted.
I shouldn't have to create a fake email account or pay someone to stop being harassed. In the end, continued solicitations after asking your account to be deleted are a form of harassment. It's no longer advertising or marketing once you ask them to stop.
You should be able to go into your email accounts settings and block emails coming from a specific sender domain, so this should be twitter.com