Yeah, but my ability to cancel is also governed by contract, not by their arbitrary policies around it. Unless the contract explicitly says otherwise, an email, chat, or phone call saying "I'm cancelling" is sufficient notice.
This would not constitute legal notice under most contracts. There will be termination instructions. Often involving mailing a letter. But almost no contract technically permits termination via phone call.
For all my web/app/software products, including streaming video services, I can cancel within the site/app. My cellphone provider is the only one that specifies a phone call.
Even the New York Times TOS says a chat with an online agent is sufficient, and that's one of the ones being complained about in this thread.
I don't think I've ever seen "mailing a letter" required outside of a few unethical gyms.