Bests & Worsts Reviews from Amazon

I recently paid off every credit card I have and this card was paid off a full 20 days before the due date via a payment online. However, they still charged me interest to pay the next month. Every other card I have treated it as payoff in full amount is the amount on the credit card bill if paid by the due date. The other cards didn't try to nickel and dime me out of another months interest charges. I will be closing this account.