On the one hand, I can see how the players would have gotten frustrated with you. It is somewhat rare (especially with the latest patch) to be able to have good duels for any extended period of time, so when people finally get the chance (on a duel server), they are typically emotional, touchy, and protective about it.
On the other hand, they had no excuse for the way you were treated. There should always be a warning first, and it should always be a kick before a ban. If you ever see me online (Sir_Ares007_HOBOBOND) and want to practice something let me know. I might be able to help you out (especially if it is melee combat).