Telecom says a farmer stung by wasps who complained she couldn't get through to a 111 operator for more than half an hour had only had marginal mobile phone coverage.
Janet Kelland says she feared she might die when she was stung hundreds of times at her property last Monday. She said when she finally did get through, an operator initially told her that her address did not exist.
Telecom's review shows several calls from Ms Kelland were answered immediately, but there was only silence.
The phone company says five minutes after the first attempted call, a connection to the St John Ambulance service was made and an ambulance sent. A helicopter was dispatched 20 minutes later.
St John says the operator took time to clarify the rural street number as it was not showing up in its system.