Have had repeated calls from this number and 5639 4289 today (8 in total) and yes switching between a male and female. The last call finally said the same, from Telstra and problem with our internet. He asked me if I was the owner of our service. I told him if he was really from Telstra he would know who the owner was. He hung up on me.

Very persistent, even though I hung up multiple times. Became angry and aggressive. Rang my partner's mobile many times ,as well. Said he was from Telstra and there was a problem with our internet .Attempted to get me to download a program that would "fix the problem". Worked in tandem with a female. Phone number was similar -(02) 5639 1498.