Suspicious.
They hung up as soon as I answered.
Then they called back - I didn't speak at first. Eventually a male voice said "hello" but as soon as I said hello again, they hung up.

Caller: Bloke

Missed calls previously but answered today and the person hung up when I said hello.
I called back and got voicemail. Called again and bloke answered, when I said I was returning a call he hung up. Blocking number now.

I call back its voice mail

Hung up when I answered - called back some guy answered and then hung up when I said I was returning the call. Called back again and it kept going to voicemail.

Called me 5 times over 4 days. No message left.