1 : what is your device ? what kind of device ? your phone ? your watch ? 2 : you are in the Garmin Connect Mobile Android forum, its not a "device" forum so you are not in the right place if you talk about a watch You can change miles to km in 2 places : on your watch (system menu) or on your phone, what did you do ?
What you have on web Connect will overwrite your device and phone's settings. You should check your Account profile's display settings and also the device's settings on web Connect. I would be surprised if you can't fix it there.
