Cards fail for boring reasons: an expiry, a limit, a cautious bank. Nothing is deleted while you sort it out. Your videos are all still in your Library, and anything already published to YouTube stays up.
We retry the charge on our own, and Settings → Plan & billing shows the next attempt as "Retry on", with the date. On a renewal you get three emails as the retries run out, with a notification in the app each time. While the charge is outstanding your plan is on hold: wherever you click in the app you land on Plan & billing, your monthly usage can't be spent, nothing publishes, and a Series skips its slot and posts again on its next day.
To clear it now:
Open Settings → Plan & billing.
Choose Update payment in the banner at the top, or Update next to Payment method.
Update your card in the billing portal that opens.
Your usage is safe the whole time. Update your payment method to keep going: your monthly usage comes back once the payment goes through, and any usage packs you have wait for you until then. You can't buy a new pack until the payment is sorted.
If every retry fails, the page reads "Access suspended, payment overdue", and the unpaid invoice sits in Billing history at the bottom of the same page with a Pay invoice link. If your card looks fine and the charge still fails, reply to this or email [email protected] and a human will read it.