exiting financial agreement

My father in law is in an assisted care home and when we were signing the paper work I signed a paper making me financially responsible if he could not pay his bills, he is totally coherent and can make all of his own decisions, they just insisted I sign. Well now my father in law is trying to make some decisions we do not agree with and I would like my name removed and the place is just giving me the run around how do I go about removing myself as financially responsible???