I called back number (03) 7037 6310 rang once then gets disconnected automatically.

They do not identify where they get your details from, and keep harassing you.
Typically they have collected information about you that is often outdated by 5+ years
They will attempt to calling from a number of phone numbers with the following prefixes
03 7037 63XX or 03 7064 14XX

Just phoned and no one there until 20 seconds later I heard a click and I hung up.

Spam

Scam