Major Issue with Testng Custom reporting using IReporter

I am trying to generate my own emailable report in testng. I am implementing IReporter in a base class and then extending base class to write required methods. But for random runs I am getting my reporter called and for others the output looks like old basic report without my changes.

package org.testng.reporters;

public class EmailableReporter
    implements org.testng.IReporter
{ 

And writing my code in:

public class EmailableResultReporter extends EmailableReporter {

And this behavior is completely random. In 10 runs near about 3-4 runs I am getting my generated report.