Call your CC, tell them they charged you incorrectly, include the page saying 140/month.
This sounds like you don't do business often (with US corporations?) They're hoping more people like you just let it ride. That's how they're making money.
Hit them where it hurts - have the bank perform a chargeback. Enough of that happens, and their rates to accept credit cards goes up.
I don't think one chargeback changes anything, but if people are more aware (not just in case of LinkedIn, but in general), this could make this shady business strategy less profitable.