Cancel this plan and end metered access (dashboard session required)

Cancels the plan and drops every API key on this account for this product to a ceiling of 0, so access ends at the moment you cancel rather than at some later date nothing would enforce. The window you cancel in is closed and invoiced first, prorated to that instant: the elapsed share of the base fee plus any overage you accrued, still under the same spend cap. The invoice it writes is returned as finalInvoice and appears in GET /v1/invoices. When Square’s own recurring subscription collects your flat monthly fee (baseFeeOwner is provider) this API cannot stop that charge, so the request is refused with 409 unless you send acknowledgeProviderBilling: true — that flag exists so nobody ends up with a ceiling of zero and a live monthly charge without having been told first. AUTHENTICATION IS YOUR DASHBOARD SESSION, NOT AN API KEY. Send the @sp/core session cookie this API sets when you sign in, from the same origin. An API key is refused here on purpose: it is a data-plane credential that lives in CI and in third-party integrations, and it must never be able to change what you are billed, cancel your account, or read your payment history. Errors: 401 unauthenticated when there is no valid session, 403 forbidden when the request is cross-origin or its x-csrf-token header is missing or wrong.