Had a similar issue and the "security department" is the way to go.
I would get someone's name in that department, perhaps try and talk to him over the phone. If that doesn't work they have a fax number and you should write a letter explaining how it was years ago your now older, smarter, more responsible and you would like to rent again with Avis for business purposes etc.....Or something along those lines.
Then follow up and they should remove you eventually.