terrible service from vodacom

i got a new samsung handset,from the start it gave me problems with whatsapp voice notes.battery goes down 20% an hour while not using the phone,calls keep getting cut off and the phone gets extremely warm while using.phone has been sent away four times,they keep telli g me they cant fi d the problem but ztill the problem persists.i sent them proof of the problems and still they wont replace the phone.terrible service from vodacom,i am very unhappy and dissatisfied