You need to WRITE to them both on one letter IMMEDIATELY to protect your credit report. Phone calls do NOT preserve your rights. This is strange situation. Obviously, at least ONE is wrong, so I suggest this.
Write a letter addressed to BOTH companies (make sure you use the CORRESPONDENCE address, NOT the payment address and be sure to include the LOAN REFERENCE NUMBERS from each organization (you might have to list all three next to their names!)).
Tell them you have your monthly payment and are ready, willing and able to pay the mortgage. However, you can't pay BOTH of them. State that both companies are demanding your payment, but one must be wrong. Demand that they produce a WRITTEN assignment or servicing agreement specifically identifying YOUR loan by address or loan number.
Enclose a copy of EACH letter you received (one from Ocwen, the other from Green Tree)
Be sure to put your mailing and contact info on it and mail a copy to both companies (keep an original for your files). If not too much trouble, send it Certified Return Receipt Requested.
Hopefully this will get someone thinking and researching. It should also assist you in protecting your credit report from any late pay that shows up, but there is no guarantee. Certainly one of them is wrong, and, of course, the one who is right will probably ding your credit automatically and tell you "you should have believed us."
If you need further clarity, please email me at MICHAEL@MIRELAND.US Answers to questions are for general information purposes only and do not establish an attorney-client relationship. This is not legal advice, simply information. You SHOULD NOT act on this information without consulting a competent bankruptcy attorney in your area and providing ALL relevant information.