Restarts payments on a paused subscription. The order's status becomes active.

• Upcoming scheduled payments go back to scheduled.
• Payments that fell due while the order was paused are skipped. They aren't collected.
• unpause_collection_config sets when the next payment is taken. Send update to charge it now and start a new billing cycle from today. Send default, or leave it out, to collect it on its usual date. These match the dashboard's Collect payment now and Collect payment on schedule options.
• A value you sent when you paused the order only applies when the order resumes by itself on its pause_until_date. When you resume it with this call, only the value sent here counts.

You can resume an order when its available_actions.resume is true. Only paused orders can be resumed.