Global Vantedge - Gvedge ruined my credit without giving information requested denied information rudness San Rafael California

Global vantedge call me at home demanding to pay the amount of $162 for an American Express card that was past due so they said.

I have closed my account several years ago with American Express with no debt.

I asked them for more information, they refused.
I asked them how to refute that they say to send them a fax which I did. They sent me a letter asking me to pay.
I sent them and American Express each a letter of dispute and asking for verification of debt which I am entitled.

I have received no answer, in less than 30 days they have already ruined my impeccable credit.
They have broken the law I believe.

Juan
San Juan Capistrano, California
U.S.A.