ACARS is purely text-based and has no voice mode. Something got lost in the description. ACARS could have malfunctioned because the radio frequency it uses was

ACARS is purely text-based and has no voice mode. Something got lost in the description. ACARS could have malfunctioned because the radio frequency it uses was occupied by a voice signal, but I doubt that the pilots would be able to state the cause of the malfunction so quickly.