My name is Nanzhi, not Zhinan

On a Chinese class, a teacher is teaching a Japanes student how to make a phone call or pick up a phone call. The teacher give student four choices when there is a phone call coming. One is “dui,wo jiu shi. Ni you shenme shier ?” One is “wo bushi, qing deng yixiar.” One is “nihao, ta bu zai,qing da tade shouji.”The last one is “dui bu qi ,ni da cuo le.” After the teacher practised all the sentences and explained for all the situations, they started to practice picking a phone call. The teacher said: “ Wei,ni hao, wo shi ...., qingwen , Zhinan zai ma ?” This student answered: “ duibuqi, ni dacuo le .” Then teacher thought maybe he didn’t understand her explanation before, so she said it again: “ nihao, qingwen, Zhinan zai ma ?” This student still answered: “ Dui buqi, ni dacuo le.” Then this time teacher really felt this student not understood her meaning.Then asked: “ Shouldn’t you answer: Yes, I am ?” The student answered: “ No, my name is Nanzhi, not Zhinan, so I said: you made a wrong call.”