Things like this are why I'm loosing faith in the entire CC industry. My main card I've had for almost 10 years. My limit is $15k on that card. Last month I got my first late charge in that entire period. Reason? I paid too early.
My bill is normally due on the 20th of each month. Month before last I paid on the 9th - well before the due date. For the next month I figure I'll knock that payment out of the way early - so I setup a payment on the 26th (almost a week after the due date for the previous payment). End of the month I get a letter from the company stating that they haven't received my payment. After checking into it I find out that though the last payment is due on the 20th, I can't pay for the NEXT month until the 27th - 1 day after I made the other payment. Any payment made between those two dates is just in no-man's-land. Doesn't count towards any particular month.
Debit cards are just as bad too with the way they work overdraft charges. My bank for example keeps 2 balances - a "Posted Balance" which is a few days behind, and an "Available Balance" which is updated immediately. Debit card transactions typically take 1 to 2 days to move from Available to posted. Transactions processed as a credit card take 3-5 days to do the same.
Thing is, they charge you a fee for overdrafting either of these balances. A few years ago I was financially constrained and tended to keep my balance pretty low. I can't remember the exact numbers, but the scenario basically broke down like this:
I have a posted and available balance both of $19. I make 3 $5 charges on the card. Posted still $19, available is $4. I make a fifth $5 charge. Now by common sense methods if I had $19 in the bank I just overdrafted once and I should get a single $40 overdraft charge right? Nope. The fourth $5 charge puts the AVAILABLE balance at $-1. So there's a $20 unavailable funds charge assessed. Thing is, the fee posts to the account the next day. The $20 fee is greater than the $19 balance so the unavailable funds charge results in a $40 overdraft charge. The account is now already in a negative posted balance. The 4 $5 charges now come through two days later and since they're posting to a negative balance account all 4 get overdraft charges.
So in the end, a single transaction over, that should by any fair measure result in a $40 fee, results in $180 in fees instead. And after you patch all this up and get your account back in proper standing? $15 fee to cancel it if you're fed up. Want to just let it sit and ignore it? They'll charge you an inactivity fee on it then (quite likely over drafting you AGAIN on that if you kept the balance at $0).