JUST had my home phone number changed to unlisted. This is the third unwanted telephone call I am getting. Came in at 7:22 pm tonight. From Paulsboro, NJ.
Anyone can call your number, accidentally or on purpose.
Being unlisted does not stop the scammers. They program their autodialers to call all possible numbers in an area code + exchange, hoping someone gullible will answer. So you will continue to get calls from scammers. What is special is the association of your name with your number. Many scammers don't even have that with listed numbers.
As your name was once listed with your phone number, it will still exist in marketing databases. Scammers that have information from those databases will still have your name.
I guess the key word there is "just", which means you number was published all those years that you had it. But even if you had it listed as private, what William has stated is true.