A Loomis Social plan is paid for one term at a time: a month or a year. It doesn't renew by itself, and nothing charges your card on its own. Plans and prices are on Pricing.
Buying a plan
Only an organisation admin can buy a Social plan. The admin picks it in the Plan step on the Connect page and pays on the next screen. If you've paid with a card before, you can choose to charge that card instead.
If your workspace is in the Social beta, the Plan step says so and there is nothing to pay while the beta runs.
Outside the beta, a new workspace can make its first drafts for free. Connecting accounts and scheduling posts need a plan.
Renewing
Renewing is another payment for a new term. Loomis sends a reminder in the week before your plan's last day, on its last day, and once it has ended. The plan runs to the end of its last day. After that, an organisation admin renews it under Settings, Plan and usage, or in the Plan step on the Connect page.
When a plan ends
Your workspace stays open and you keep everything in it, to read at any time. Drafting, scheduling and publishing stop until the plan is renewed, and so do your comment rules.
Any post scheduled after the plan's last day is held. Nothing is deleted. Renew at least an hour before a held post's time and it goes out as planned. A held post whose draft changed, whose approval no longer stands, or whose time passed while it was held stays off, and you can schedule it again.