I got that e-mail too, on a decade-old test account: first an e-mail that reads like my account simply "expires" if I don't update. Then an invoice. Here's what I don't get: After a stunt like this, any reputation/brand value that you might have had is gone. So, the obvious conclusion is they bought the company purely to pull this trick. Any other value the company might have had is deleted. Can that have been worth…
Someone once told me that as recently as the late 2010s AOL was making millions of revenue off of old dialup accounts from the 90s that people just never cancelled and the cards just kept running. That's what they're probably shooting for here.