Auto Finance Problem

I had purchased a car in 1995...In the beginning it was finance in my dads name, and about midway through, had it switch to both mine and his. The car was financed through Ford on the 5 year plan. All of the payments were $315, with the exception of the last one which was around $230 (I figured since in the past I had "postponed" payments, where they were added at the end, and the odd amount was just interest that added up). When I was trying to buy a new car in July, there was an amount of $678 still on the credit report through Ford. I thought the credit report wasn't updated since the final pay (of $230) on April 20..which I admit was 30 days late. I called Ford up, and they informed me that, "the payment was 70 days late (the date they gave me for the final payment was June 27), and they tried to repossess it, but couldn't find it and that they 'charged off' $140". I told them that I wasn't aware of the "charge off" and that I was willing to pay it (when I called for the final payoff I was given the balance of $230). They told me the only way to remove it was to prove that every payment was on time, which would have been impossible. Now I was NEVER called, NEVER received a statement about them "trying to repossess" or about the charge off. Are there any actions I can take to have this resolved? Not only is it affecting my credit, but my fathers as well. Thanks