I have refinanced my loan and closed it before it was transferred over to a new lender, but they say they might not honor it

I have refinanced my mortgage and close it ( I have the docs to prove it), but the new lender will not retun calls saying they are buried knee deep. I did speak to customer rep who said that they might not honor the new refinanced terms because the prior lender went bancrupt. I have been paying the original payment for the last 2 months, and no relief in sight. This make no sense. Can someone help?