I was turned down by Capital One Auto Finance and can't seem to figure out why. We've had 2 auto loans thru them and paid on time everytime. We have one that is current, the other was traded in. We also have a credit card that we pay on time. Our credit scores are around 620, which I know is not the best, but it is better than last October when they were around 580 and they financed us then?!? The only thing I can think of is that we had an issue at my bank where the bank placed a stop payment on my car note by mistake, which meant my payment was like 15 days past due. Totally not my fault as I paid the darn thing 4 times during this month and only one went thru the bank after repeated calls to both capital one and the bank. I think this may have something to do with it because when I applied my payment was showing past due, even though I paid it. Anyone think of a reason for the denial. Or know how I should handle? I've called and all they'll say is they've sent a letter.
Additional Details
More info...

I originally have the payment drafted from my account on the due date (5th of the Month). The bank put the stop payment on it and the money was returned to my account on the 7th. I called Capital One and the Bank and made another payment (through the internet) I also told the bank to remove the stop payment. Capital One is saying that this was also returned for stop payment but the bank says that it never went thru a second time. I kept calling Capital One and they kept showing it current and said that it could take 10 - 12 days to clear my account so I waited and then that one came back as a stop payment. I just made the 4th payment online yesterday and it finally came out of my bank account today! It's not reporting to the credit bureau yet as it is only 15 days past due and they told me that it had to be 30 before it would report.

Also, we make 75,000 annually, which is about 10,000 more than we made when they financed us last time.