When I answered there were several seconds of silence, then background sounds of what sounded like a call centre. I said "hello" a couple of times but got no response, then the call was terminated from the other end. When I called the number back a recorded message told me that I had dialled an invalid carrier access code. Obviously someone had hi-jacked the number and was setting up some sort of scam.

Caller: I dont know

Blocked and sent to scam by my phone.

Went to voicemail, no message left

Robo call-Said they were from Visa. I hung up and blocked the number

Another scam ... call went silent when answer. .

Caller: Call centre

Scammers from an overseas call centre.