So another techy student solved the puzzle, here are his "instructions" so maybe some other people can solve the above issue:
To do a Microsoft Excel factory reset there are several issues
one of them the sync all over the system so even if u delete and reinstall the previous changes will be automatically added.
to solve this you have to find the connected data in the windows registry files and erases them and after reinstall the excel
in this case you can start over clean again
you can do trough the windows registry editor or in the terminal with commands
I hope my short explanation can help :))