Called me asking for my tenant and mentioned the rental address. Also said it was 'Joan' calling.

I received a call from this number at my house, and they said its a personal matter, and there name is Joan. But I don't anyone from Sydney called Joan, anyone help please?

I have got messages from a women or guy when I ask who they are they cant tell me who they are now they ring my work saying there friends of mine when I have rung back they wont tell me who they are and what company it is when I ask that this is a scram they hang up.