Ok well I can not stand debt collectors, although I understand that they are doing what they believe is their job. You need to read the agreement that you signed with the collector and if it is not what you understood it to be then I would speak with an attorney. First, you have the right to validation of the debt which includes a copy of your original agreement with the college, a copy of your pay out (all payments made) and a copy of the agreement between the debt collector and the college that allows then to collect the debt on their behalf.  This agreement should give you some insight in to the mechanics of the matter and possibly the contact people involved.  Then I would also call the college itself and speak with their financial office.  You can absolutely speak with them about settling the debt if they have not already sold it.  And even then the collections people have the right to settle it as well.  Good luck.