This is usually just the way the game works. Some players only use their challenge screen, and as a result get random opponents who may or may not be good matches.
I have a few dueling buddies, we do some friendly trash talking when we duel each other. But for the most part, duels don't stay even in this game. One player will tend to get better faster than the other, and then it is all one-sided.
My advice:
1) If you aren't actually being bullied, don't take it personally. The vast majority of the time, someone is just trying to get more duel epics to sell.
I don't even duel for glory. And I literally don't have enough opponents that give me more than 20 glory. If I want to use all my courage in a day, I have to take 'bullying' duels for tiny amounts of glory. (That is almost certainly not the case of a level 111, though.) I want the duel epics, and the notes they produce, and the skills they buy.
2) Have you tried politely asking the player to stop? By politely, I mean just that. You are, after all, asking for a favor. Keep in mind that *demanding* that someone quit hitting you is quite often counterproductive.
Personally, I have had people threaten me, say they will hit my friends if I don't leave them alone. I don't go out of my way, but those players ARE still on my hit list. On the other hand, I have 7 or 8 players who asked me to stop, quite politely, and I skip over them without a second thought. Even if someone is on my hit list, though, I try to be aware. If someone is getting close to an achievement (like 300K glory), I leave them alone until they get there.
3) If you ARE being bullied, actually being harassed, submit a ticket with the name of the bully. Someone dueling you, then taunting you, sending bullying messages, demanding something in exchange for stopping the duels? I know for a fact that harassers are dealt with. Don't put up with that kind of crap.
4) And the last and best answer: Get better. It can be quite satisfying, turning the tables on a player who has been farming you for a while. Just try to keep it civil... don't turn into a bully yourself.