The email lists sites, yet we can NEVER remove a site from our account. Even "deleted" doesn't mean deleted. Adwords has issues.
edit: You mentioned your sites are established and of decent quality but that must not be true. Google doesn't want you to rank well naturally and now they don't want you to pay your way into the infamous top 3 results of every page. Google can't be wrong, about anything, ask them.
How times have changed.