I'm on a Galaxy S6 Edge, and my friend reports that my texts to him come through 2, 3, and sometimes even 4 times. This happened with my old phone (Galaxy S3) as well. I'm using the native texting app; he's on iOS/iMessage. No one else has told me that they are getting duplicate messages. I've tried deleting his contact as well as deleting our text message history. Any assistance would be appreciated.