Affidavit of Heirship does not apply in my situation

so need more assistance. property is in florida. reverse mortgage co. has assigned mortage to foreclosure company. still insists on needing "letter of authority". company i am financing through insists i get "permission" from reverse mortgage company to refinance. does anyone know what a "letter of authority" is. the property was quit claimed to mom and myself prior to her passing as joint right of survivorship. no need to probate will. will does not mention house. mom had no other assets. i filed death certificate already. i was going to go to county recorder today and see about getting mom's name off of deed. should i have lawyer draft up new deed? should that be a warranty deed? help!!!!