To cancel, go to Billing → Plan and select "Cancel subscription." You'll keep paid features until the end of the period you've already paid for; we don't prorate cancellations. After that date your account moves to the Free plan rather than being deleted, so your data stays available.
If you cancel by mistake you can resubscribe before the period ends to avoid any interruption. Cancelling within 14 days of a charge may also qualify for a refund under our refund policy.