Generally speaking, payments are automated as long as you provided a credit card / paypal and haven't hit the cancel button. However, to check out your billing options for your server, log in, go to the "Info" tab, and then scroll to the bottom. You should see "Billing Options" including upgrading/downgrading and cancellation.
Hope this helps.
That pretty helpful. And I got an invoice about it.
Also how can i change the subscription? Like i wanna pay 3 months at a time instead of paying monthly.