Americredit charged off my car loan!!!!

I need some help. I had a five year car loan, paid on time every month, I did have two deferrments, the first was in 12-02 and the 2nd was 12-04. One a medical emergency and the other just Christmas time, After making what I thought was my last car payment in february 2007, I decided to check my credit reports, I was planning on buying a new truck and wanted to make sure my credit reports were in order. You can imagine my total SHOCK when I found my car loan listed under the negative list of accounts!!!! They charged my account off in January 2007 without ever notifying me at all, no phone calls, nothing in writing, I had no way of knowing this. It showed that I was 120 days late even though I had sent in a payment October, November, December, January and February. They charged it off after 3 months and I was still paying. Apparently they said my loan had become due October 2nd, there was still 700.00 balance owing. Had I known it had become due at that time I would have paid the amount owed but no one contacted me about this. I am so upset, I made sure I paid my payment every month on time never being 30 days late ever and yet they show I was late OCT, NOV, DEC 2006 and once in SEP & DEC 2004 which I have my bank statements proving I wasnt late, the DEC 2004 was the month it was deferred. I disputed it but they refused to remove it, This has totally destroyed whatever credit I worked so hard to build back up. I dont know what else to do. I need a new car and I shouldnt have to pay a high percentage rate because of this. They didnt even show it paid on my credit report. What recourse do I have at this point? My credit score was 637 its dropped to 548, I thought about hiring Lexington Law Firm to help me with this but then read so many differing accounts about how they can mess my credit up worse and that its not a good thing to use them, also that they will be listed on my credit report as a "credit counseling repair service" which is just as bad as having bad credit.
if we dispute something that is over 4-5 yrs old and the credit bureau says its been verifed, how do we know how they verified it? Just because they said they did? Last question, how many times are we allowed to dispute something? Any help would be greatly appreicated.

 

I did contact the company but they still refuse to remove the incorrect information. They said I was late 120 days since the loan had matured on October 2nd so how then did I still have a balance left over? I continue to make my monthly payments until February. I dont know what else to do. A question, when does the thirty days start? after the 10 day grace period or from the due date? say its due on the 2nd of each month but isnt late for ten days later, does the 30 days start after the last day of the grace period or from the 2nd?