How do I change or cancel my plan?

From Settings, with “Upgrade Plan” or “Manage Plan”. Upgrading is immediate: you're charged the full price of the new plan, your cycle starts that day and the new plan's tokens are added to your balance. Downgrading or cancelling takes effect at the end of the period you already paid for: until then you keep your plan and your tokens. When you cancel you move to the free plan and keep your balance.

To update your card or see your invoices, use the payments portal that opens from the same place. If a renewal payment fails, the plan stays active, but tokens aren't topped up — and you can't buy tokens or change plans — until you pay the pending invoice.