Responsible party

I work in a pharmacy where  we supply medicine to nursing home nation wide.  I am in the admissions department.  Where one of my job is to make it sure we have the correct responsibles party address.  Especially if they are paying private whick means they have no insurance to pay their meds.  We make it sure we verify the address.  If for some reason we can't find any address we local yellow pages to search for addresses and double check @ USPS.com if it is the correct format and can be deliverable. 

Sometimes we are having hard time to find some correct address.  But we will try different way just to obtain information.  Local search is usually the top option.  If not then we will try to call the facility again hoping to give us information we needed.