Trying to figure something out

Ok I looked at my account on my phone to get exact details on my account and charges. All the sudden it pops up and says I owe 400+ dollars. Then it informs me my auto pay didn't go through on the 24th of last month meaning I lost my auto pay discount. Then I go in and charge the same card . So I owe more for absolutely no reason at all and no one notified me in the last week.