Ask HN: Any legit reasons for non-self-service service cancellations?

Recently I've had several frustrating instances of being able to self-service signup for some paid service but then when I end up wanting to cancel it, it is not as easy. Generally in these cases you have to email them requesting a cancellation, and then they may have a follow up email requiring you to confirm more details. In a rare (and exceedingly frustrating) instance they required you to call them in order to cancel.

In my mind, this is a shady business practice which should be regulated against. If you can sign up in a self-service way, you need to be able to cancel in a self-service way. The way I see it, the businesses who do this are not proud of/confident in their product/service and want to make sure they keep some of the recurring revenue from those who can't be bothered to go through the more complicated cancellation process (especially if it is a low monthly cost service).

I would love for this to be something regulated, but at the same time large brush stroke actions are risky and can negatively affect groups you didn't realize.

I'm curious if there are any legitimate reasons why self-service account cancellation is impossible when you are also able to sign up and pay for the service on your own.