There's nothing more frustrating!
Federal Law requires that someone take you "off the list" if you specifically request it. You probably need to be clear - "Please take me off your list".
I believe there are exemptions if you have a business relationship...but my guess is that it's a grey area for marketing cross sells.
I gave up American Express 20+ years ago and haven't missed it a bit...cancel the card and there's no longer a "business relationship" exemption.
If you don't grow where you're planted, you'll never BLOOM - Will Rogers