It appears more people have this problem and there isn't much of a solution from the Tech guys.
and play campaign from the start again. The campaign patch while some didn't finished the campaign yet probably messed something up. I just guess that so no guarantee.
I am very sorry but my answer was incomplete:
Your online player account cannot be reseted, only your ingame progress.
1. Click on Windows Start button then on the Windows username link present at the top right.
2. Open Saved Games folder and delete EugenSystems folder.
1. Click Windows Start button then Computer.
2. Open Local Disk (C:).
3. Open Program Files or Program Files (x86) folder.
4. Open Steam folder then userdata folder.
5. Open your Steam user number folder then the 58610 folder (58610=Steam code for Wargame EE).
6. Delete Remote folder.
7. Run the game.
Thanks to [EUG]Furios
You lose everything however and start from the very beginning.