There is no rule allowing players to have two nations. One nation per player, no exceptions.
Since you were not banned, you may log into the account you wish to play with and create a new nation.
Looking at updating these. The following alliances are eligible to be added, provided they submit images (150x50 pngs):
CLAWS
Freehold of The Wolves
Knights Of The Round Table
Only nations in existence after February 7th, 2014 are able to be restored by logging in again. By the looks of it you last played several years prior to then.