In the past when I've had to deal with a retention person and they ask why I'm leaving, I usually just say personal reasons. I've had pretty good luck with that.
In the good old days of paper delivery I used, "I'm moving to Zimbabwe." They never had a checkbox for Zimbabwe and the call ended there. Now, I guess they'll just pitch the online edition.
Maybe I'll try, "I'm about to winter over in Antarctica and won't have the internet bandwidth for your paper. Do you guys deliver there?"