Caller: Someone claiming he's from NBN

This guy spoke with an accent, introduced he's from NBN, saying my internet has problems. I replied that I have no problem with my internet, it's working well. However, the guy kept saying my NBN is not good. I really had no idea what he wanted to say. Then I asked him if he was really called from NBN, could you tell me my account name in the system? Thus, he replied rudely, "yes, I know your name, your name is son of the b***" Not sure it's a scam call or a prank! I cut the line immediately.