Cash on credit card by mistake

molerat

They will pay off the last statement first.

Then non statemented items by highest interest rate in date order.

Some cards list certain categories will override the date order but not NW.

Fingerbobs

I'm actually really surprised they didn't just waive the fee and interest as a goodwill gesture. They did it for me, admittedly quite a few years ago, when I made a similar mistake, and other card providers have done the same for my parents when they've made similar one-off goofs.