How I can get back my old account if doesn’t show in my app, or all my dives on the watch
How I can get back my old account if doesn’t show in my app, or all my dives on the watch
Not sure I understand correctly, but if you are logged into a wrong account, then first of all export all your activities from the wrong account, so that you can import them later in the right one. Then remove your device from the wrong account on all Garmin app you use (Garmin Dive, Garmin Connect Mobile, Garmin Express,...), sign out from all of them, and then sign in back into the correct account using the original credentials (email and password), and import all the missing activities.
Find more details in the document Data is Missing from My Garmin Connect Account After Syncing | Garmin Customer Support