In the past once I've reached someone who acknowledges they're late on the payment, I've offered to waive late fees if they pay immediately that day. It's usual

In the past once I've reached someone who acknowledges they're late on the payment, I've offered to waive late fees if they pay immediately that day. It's usually good incentive for them to actually pay. I'd ping them weekly in different forms for a few weeks. Then I'd wait another few weeks and then file a small claims case and send notice via certified mail. And mention you'll drop the case if they pay prior to trial. But 5 days isn't very long. I would assume the best and remain cordial throughout.