Etek 5 problem

I have this pe etek 5 with oled I purchased new a few months back. I’ve only used it like 2-3 times, worked great no problems. Then out of no where the gun went into setup mode and will not exit the mode, the marker will not shit off either. I have to take the battery out in order to shut it down. When battery is put back in marker still is in setup mode. Anyone have a solution to fix this problem