Any subscriptions you've obtained through other services (Hulu, Prime Video, etc) will have to be unsubscribed through those services.
Any subscriptions obtained directly from the channel will have to be unsubscribed on the channel's website.
Note that most (all?) subscriptions pre-pay for a defined subscription period and auto-renew when the period expires. When you unsubscribe it stops the auto-renewal but the current subscription stays active until the pre-paid subscription period runs out. This is all explained in the conditions you agreed to when you subscribed -- you know, the stuff you agreed to without actually reading it.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T