Responsible for mothers care bill?

My mother was in a non-profit facility that sold. The non-profit employed a company called Medicaid Done Right to help us with Medicaid. Medicaid ended up denying a span of care because we were told we could use some of her money to prepay her funeral and now they are saying we couldn’t. Are we responsible for the bill for the time they denied her? Also my sister is POA and signed papers when mom went into the facility. Instead of them going through the paperwork with her, they gave her the papers to sign so she may have signed a financial responsibility form. Is that binding if she did?