For the uninitiated; unsubscribing from a mailing list should not take 7-10 business days. It certainly does not take them that long to add you to the mailing list; so why would it take that long to remove you? Certainly there are no humans making decisions or manual database deletions… in that case it would actually cost the marketer more to delete than acquire the eyeballs.
The fact is, they want 10 days (a) to sell your contact info to someone else (b) spam the crap out of you over the next 10 days © hope that by day 10 you’ve forgotten and … maybe… you’ll try to unsubscribe again.
It would be great if google could enhance their email product to do some inbox magic in this space.