Starting ringing today. Seems to be from Bosnia. Hangs up when call is answered

it was recorded on my account as International voice

got call yesterday, didnt pickup

I got the same call last night but didn't answer

8.23 pm call from Bosnia & Herzegovina - they hung up after 3 rings. I wonder if I have won the lottery I didn’t have a ticket in? Or was the bequest from a rich relative? Or maybe something simple like the Tax Office collection of debt advice?
Most likely is the the fact my computer has an incurable virus which can be rectified after a small/medium/large/crippling payment??
Guess I’ll never know . . . . . . . .