Hm. Hetzners billing stuff is highly automated - but they usually give you about a month to pay your bill if the credit card payment failed for some reason.
Have had some hiccups with payments not going through myself that ended up in server IPs being restricted but they were very helpful on the phone and service was restored in about 30 minutes after the call. Decidedly not ideal but has been easily manageable since.
We were on invoice, and yes we had about a week or so of warning, but again, we had done the wire transfer to the full amount, and provided evidence of such.