My credit card is with Capital One. I'm sure Chase would reverse the charge as well, as this is an "unauthorized" charge (once you've canceled). LDSmovierentals.com has not contested the reversals.
Yes, I also tried to change my credit card information through their website and the page wouldn't load. And since this whole problem started, they've added a "cancel" button on their website. So I tried that and I got an email saying they'd cancel my account and stop charging my visa once I had returned all the DVDs. Well, like you, I haven't had any of their DVDs for several months now, and my account information shows that I have none in my possession!