Are we responsible for mom's rehab bill while waiting for transfer to another facility?

Mom was admitted to a rehab facility after she was hospitalized from a fall. After a week, blue cross Medicare dropped mom due to a delay on her renewal process. She still has Medicare and Medicaid but not the blue cross kind, just plain Medicare and Medicaid. The facility only will accept blue cross Medicare and plans to transfer mom out. So we are waiting for another facility who accepts just the plain Medicare/Medicaid plan to accept mom. So the question is are we liable for her stay at the rehab while she is waiting for another facility to accept her?