How to resolve unable to block unwanted roadrunner email?

I am operating my official tasks with the help of Roadrunner email services. I know very well that I use it for higher speed emailing services that offer effective and smooth communication. It is known as a safe and secure mode of communication, which sends the required information from one side to another side. But from last a few days, I am facing problems to block the unwanted Roadrunner Email. I am getting a lot of trouble for resolving this issue. So I am missing something very simple. So please someone can suggest the simple tips to resolve this issue.