It's possible that your TrackR device simply needs to go through a battery reset. To reset the connection, turn off bluetooth on your phone then remove the battery for a minute then reinsert. You can see how to remove the battery with the following video:
Press the button on the face of the TrackR after reinserting the battery. The TrackR should light up and beep. If the device does light up and beep, turn bluetooth back on and open the TrackR app. The device should now be connected. If the device does not light up and beep or reconnect to your phone then you may have a dead battery.
Need a new battery? Order replacement battery here >>