Have you tried Truecaller? It will show you if it's a spammer or not and if you setup the app as the default phone application, it can automatically block the c

Have you tried Truecaller? It will show you if it's a spammer or not and if you setup the app as the default phone application, it can automatically block the calls, you will just get a notification that xxx [spammer: XYZ] phone number was blocked. In Greece there is a law '13th article' that every telephone company must have a list with the numbers that doens't want to be called by spammers. If you are listed in this list and a spammer calls you then you can press charges. Isn't such law in your country?