My phone keeps receiving a single message from a friend, constantly, every three hours. It does not show any delivery on my friend's phone, it's just me that receiving it. What can possibly cause this issue and what do I need to do?
Generally multiple text problems are caused by an intermittant connection. The system sends the message and you receive it, but your connection isn't stable enough for the system to be alerted that it was received so it sends the message again.
Try refreshing your connection by putting your phone on airplane mode for ten seconds and then disabling airplane mode.