I'm always surprised at how "easy" it is to pressure litteral billion-dollars companies like Visa and Mastercard, don't they make "fuck you money"? How are you even going to cancel them? They're hegemonic.
People assume it's pressure and not the payment processors looking at what people are complaining about and independently deciding it is too risky.
These are the same payment processors that stopped allowing payments to porn sites due to the epidemic of 'revenge porn'. I would argue that was a net benefit to society as now these sites only allow 'verified' uploads.
When you tell them something they want to do anyway, you only need a few calls to confirm their bias. When it's something they hate, they will throw millions to resist the change.
It can't be cancelled, but it can be inconvinienced. Emails can be ignored, but snail mail is overwhelming, and call centers can be gummed up. For some reasons, these businesses respond more to these old medium, so gotta make use of it.