Question about Amex American Express Charge Off

Hi, I came across your blog searching the web.  Thank you very much for your blog and in advance for helping me with my question.

I have a charge off with AMEX.  It is for a small amount, $250.  The account was closed on 11/2003 and the amount was reported as charge off.

It has been years since I received any collection letters from AMEX or any credit agency on this.  It is however affecting my credit score.  I would
like it to be removed.   I disputed the charges with the three credit bureau and they all said that the charge off has been
reported correctly.  What do I do next?  Could I even pick this up with AMEX?  Paying it is no problem for me but I like in return for this to be changed
to something that is less damaging to my credit score.
———————
My Story
I got charged off at bp oil for 300 bucks
1 year later i wanted to make it right
i called them and explained the circumstances that caused my charge off and that I was a good person who wanted to make it right now that i was back on my feet
We all agreed if i paid the amount owed and added another 250 they would open that same account number again and allow me to better my credit
 
i did this for 12 months and paid them 30 or 40 dollars more than i charged each month
at the end of twelve months i had a 600 dollar credit and 12 months of good credit
 
i called them and asked them if they could only report the past 24 months activity
they agreed and now i had a , credit for 600, 12 months good payments on my report, no late payments showing for that account