Claimed to be from a currency trading company, referred by a third party

I called back number 0466 330 710 reached voice mail but did not say for what company.

Had a missed call, with no message. When I called back I heard that the mailbox was full.

Called at 3.55pm but didn’t leave a message

Claimed to be from some currency trading platform following up from a call to me a year ago - said I didn't think so (sounding unimpressed) said they would remove my number from their list
Was also a lag between answering and someone speaking which automatically made me suspicious it was an overseas spam call

hung up when I said 'hello'

This number calls regularly, I answer and they hang up without response. I call the number and get "this voicemail inbox is full". Starting to really piss me off

Did not answer and didn't leave a message.

Called but didn't leave a message.