If you are using a land line, I do not think there is a way to block phone numbers. However, if you are using a cell phone, there are settings in your phone under ‘security’ that allows you to block calls. Most phones are general when in comes to block calls. For example, you can only block all incoming calls. However, there are a few phones that allows you to put people in a group and block that group and some even allow a single phone number.