Don't let the payment fail — committing to a path early, before the date arrives, is what protects your Split Pay account.
Important timing:
You can change your second payment date up to 14 days from your original due date — that's the outer limit for a full date change
Past 14 days, the date change option isn't available anymore
The worst option is letting the payment just fail. If it fails:
You may get hit with NSF or overdraft fees from your bank
Your account stays frozen until the balance is resolved
The longer it sits, the harder it gets to fix
Eventually accounts in this state go to collections, which can affect your credit
Waiting it out is the only option that consistently makes things worse.