Telstra say it is unacceptable the company did not make earlier contact with the family of a woman who could not get medical help during service outages.
Anne-Marie Rankmore found her 75-year-old mother unconscious on the floor of her Proserpine home during the Australia Day long weekend, when the network suffered a massive failure and the triple-0 service did not work.
Ms Rankmore says in the week after her mother's death she tried several times to contact Telstra about the incident.
A Telstra spokeswoman says Ms Rankmore's call was not responded to in a timely fashion and it will investigate why that occurred.
She says after the investigation appropriate steps will be taken to help ensure similar calls are given the respect and priority they deserve.