IBM Collection Agency?

I had an account charge off and was told to call IBM. Does anyone know who they are? I think they are a collection agency. I called and they said they were part of the company I tried to settle with (unsuccessful & offered 50%) and can now offer 60% to settle the acct. Now 35% is what the creditor can get for tax write off. Can anyone help me figure out who I'm talking to and how to negotiate with this new group of folks. The damage is done with my credit. Now negotiating how much to settle for.

Thanks!!