I agree. I think that you need an attorney to get something like this worked out. Is there any chance that you can pay the balance in full? Some companies will negotiate if you can pay what you owe in full (the $4500)?
I am worried that getting an Attorney might cost you $2500. You might be able to hire an Attorney and pay by the hour. Have him draft a letter to the Credit Card company using whatever lingo. That you were able to pay off the credit card companies that worked with you is in your favor. Do you have documentation that you tried to call and be pro-active with this particular company? Names, dates, etc?
Another idea might be to talk with someone higher up at the company. For instance, I work in the medical field and they have people there to specifically help with certain situations and who have autonomy to make big decisions like this. Talking to someone who has no power is not going to get this done. I know that their are Appeal Boards where you can present your case. If you haven't already done this, you might call the Credit Card company and tell them that you would like to put an Appeal and present your case.
Hope this helps. Good luck.
N.