Why do these f*ckers keep ringing?

Caller: Did not know but now I do

Unsure why they rang me but its been blocked. Looked up online and it says they are a software company in Sydney called F-Netsip or just Netsip. Here is the info: ------"Netsip, a company providing telephone, voice, and data communications services, may be calling you for legitimate reasons, such as to provide services or for marketing purposes, or potentially for a scam, so it's important to be cautious and verify the call's legitimacy. " - Yeah, blocked. You're welcome.