Well, while you can't really stop them from calling, you can stop them from coming through to you, and just go straight to your voice mail.
I have seen a few apps on the Google Play Store for this. Many of which are free. But it is kind of hit and miss with what things they want from you. I am not a fan of apps that require all kinds of access to your phone or personal info.
You might also try contacting your service provider/carrier. Some have the option (either by calling in or visiting your account on their website) to turn on blocking of such numbers.