Sounds like you have an age bug in your system Demonik1 - LOL You may find other things get affected by this bug too - I have ;-)
I have been above level 720 for a minute now, and have never seen a Valhalla Viking in VC. Other people around my level have a few scores against them and even people below my level have a couple of hundred. Is there a limit on who can attack them, or do they stop appearing if you are above a certain Battle Strength?
They only appear if there aren't many live active players healthy enough to attack. There have to be fewer than 20 or so healed live players on the battle list for the valhallas to appear. You can submit a ticket to Support to be sure, and Kano can take a look at your account and fix a problem, if there is one.
I doubt there is a problem, I stepped away from battling except for the DP minimum on account of too many people getting other higher levels to do their dirty work for them. Would there be a different visual appearance to a Valhalla Viking, or is the only real noticeable difference that receive no money from them?
I finally got to battle a Valhalla Viking or two, It happened just when I reached 75 days. My entire world changed for the better!!