Green Tree Servicing LLC , Conseco Collecting a debt St Paul , Minnesota

Our equity loan was sold to Green Tree Servicing by GMAC.  While we were notified by GMAC of this pending action, we did not receive any information from Green Tree.  Our GMAC account was set up with auto deduction, and specific mailing instructions to a Post Office Box.  Our first contact from Green Tree was in the form of a VERY impersonal message left by a customer service rep.  It was a first name basis only, and no mention of who she worked for or the nature of her call.  Just a hi, this is (not giving name) I need you to return my call at xxx-xxx-xxxx.  The call was returned and were we surprised.  They are claiming our mail was returned and our payments were two months behind.  This is not off to a good start.  How could they not have all our information?  GMAC always mailed to our box, not the street.  And, there was no assumtion of the direct payment schedule.  The differences seem to be worked out with the customer service rep that handled our call.  We will wait to see if there is any fall out over late fees or notes on our credit report.  Overall, we very unhappy with the way this has transpired and the lack of professionalism.