Pending FBM Replacement Order

Hi there – I have a customer who purchased an item that they broke upon first use. The order was FBM. I promptly messaged the customer and let them know I would be refunding them immediately and they wouldn’t have to send the item back. I issued the authorized return a full refund. After I messaged them, I noticed they submitted a replacement order but the order has been pending for over 24 hours now. I wouldn’t think that a customer would need a valid form of payment for the replacement order but I was curious if this could be a scam of some sort.

Anyone else have experience with this? Any feedback on how best to handle this? Should I wait for the order to stop pending before I send them a new one? Or can I send it right away.

Thanks in advance!