Hello X0009X! We regret that you have such a bad experience.

Can you take some screenshots of his messages and send in private message? If he insults you we can take care of it. What can you do right now: Elders and Chief of your clan can clean your clan's wall from any unwanted messages. You also can add this player to the blacklist, he cannot write to you in private messages. But as the Vikings are a social game, the best way to solve your problem is to try to negotiate with your opponent.

Yeah, it's called "taunting". If it's not against the terms of use, which would be racially, religiously  (etc) motivated, then it's ok...