Don't Hang Up! (1974)

Sinopsis: A young woman, Amanda Post (Susan Bracken), is summoned to the house in which she grew up to attend to her dying grandmother Harriet (Rhea MacAdams). The place holds bad memories for her; as a child, she witnessed the murder of her mother there, and the mystery assailant was never caught. On returning, she encounters three sinister individuals: Doctor Crawther (Jim Harrell), who refuses to admit the sick woman to a hospital and insists on administering her medication himself; Judge Stemple (Gene Ross), a corrupt local magistrate, and Claude Kearn (Larry O’Dwyer), curator of a nearby museum, who is angling to inherit the old lady’s collection of antique furniture, garments and jewellery. Amanda gives the three vultures their marching orders, only to find herself targeted by a menacing phone caller who knows her every move…