Looking for help in finding out how message are are to be received on my device

[364305]

 I am receiving messages notification yet when I go to my task bar it's gone also what all is need for some to copy my device. I recently add a watch to my service and. When I set it up and installed wearable on my phone when it synced someone else phone contents were merged with mine days later my watch said it had been transferred to a different phone ???? I am so lost . Lastly I found out I had a Samsung account and logged in and 

This is what I saw . I signed out of the other device with the option given. And today I log back in and sure enough it. Signed back in.

 Is there way to communicate via Samsung or some back door. I am unaware of. Most importantly how do I get this device from accessing my phone and all my accounts thank you for any help

[meself]

Did you log out both Google and samsung on the 2nd phone under devices

[364305]

Yes. Right after setting up the watch and realizeing if their contacts synced to my phone the mine must to their. I immediately got the phone and logged out of every account plus went on Google and logged out. I only found out About this Samsung account 3 day ago

[nullandvoid]

Change the passwords on your Samsung and Google accounts. Or log your phone out of those accounts and create new accounts. Download you contacts from Giogle first, then delete them from that account. Import them into your new account. Do you know the person whose device that is?