Obnoxious to be sure, but it sounds more like incompetence than malice. If it were malice, they'd be much more eager to respond to you and immediately credit you for the trouble to keep you quiet while they continue skimming off the ones who simply don't notice.
Also, Hanlon's razor...
Any company that would charge your account and then deny that it is going on, which they did multiple times when reaching out, is questionable in my opinion.