Let's send out the search party and find Yahoo Messenger on your phone.
What phone do you have? If you have the Note 3 you can follow these steps http://vz.to/1l3N2sH to uninstall 3rd party apps. Please keep in mind that you cannot uninstall apps that were preloaded on the device.
Are you also having issues with the battery? Please provide details regarding your concerns so I may better assist you.
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