All they said was nonsense ... Why do you guess if you do not know the solution???
motherboard problem, memory failure component 100%
There is a solution, need to replace the memory component.
You will have a hard to find someone who can perform the repair, it is a soldering and then need to burn imei and Android files.
This is the same component as the Galaxy 3
All your information has been lost
https://www.youtube.com/watch?v=HdMmXT5gn7A
https://www.roytanck.com/2013/06/04/note-2-update-sudden-death-syndrome/