Caller: NBN internet

I had a call from a private number from the "NBN about my internet". Apparently there is a problem with my internet and they were calling to fix it. I was told that someone was trying to steal my information (ie them!) and they could show me the errors and help fix my internet. I played along for a bit. I was questioned on how many devices we have using the internet at home. I pretended to not be able to hear them anymore. She got her supervisor and same problem, I pretended not to hear! The supervisor then called me back from this "Melbourne" number. I told him I thought I had a problem with my phone as I was struggling to hear. I again acted like I couldn't hear him. I heard him comment the line was dead and he eventually hung up...