This isn't a Comcast subscription. This is an enterprise software deal that costs many multiple thousands of dollars. Anyone that thinks that Carta was ever going to go "Oh, sucks to be you, you couldn't schedule your cancellation meeting before the renewal date, well, tough cookies, you have to pay us $18k for your next contract year" simply doesn't know how enterprise software deals work. There is no need to get a lawyer involved because all you have to do is call up Carta and say "Your shit is broken, there are no cancellation meetings for weeks."
To emphasize what I put in some of my other comments, sure, Carta needs to fix their shit, and I think the Techcrunch article is making it more about the fact that you have to have a cancellation meeting in the first place (which is a valid compliant), but this idea that it's some deliberate form of "dark pattern gotcha" just belies a misunderstanding of how enterprise software subscriptions work.