Hi to all mates. I’m in trouble with the attack granted by my marking ability, because my DM attack always me. Ok, I’m a defender, so it’s correct...but I have many feats that enhanced my "Challenge attack", like Staggering Challenge, Devoted Challenge and Mobile challenge. It’s hard for a defender to use his "marking attack" if his role is to take always enemie’s blows and DM litterally do that. Ty for suggests 
Just because you're a defender doesn't mean you should be being hit all the time. There are occasions when a monster would ignore the mark and attack someone else. If your DM is chosing to run the monsters in such a way that they always make the most tactical choice, he needs some roleplaying help. However, it really isn't that bad unless you are dieing as a result.
Get the Rogue to provoke some OAs. Either the DM attacks you, or the Rogue gets to walk around his monsters (into flanking position).
If you don't have a Rogue, get someone else to provoke OAs by flanking. If the DM never uses his OAs, take advantage of that.
Cheers, -- N
You win either way, that's the cool thing about the ability.
If the DM is treating the fighter challenge as a guaranteed lock-down, then the rest of the team can take advantage of this.
Remember, as a fighter, you don't *have* to mark an opponent when you attack it. If you're in the process of getting your butt kicked because you've marked something you can't handle (and you're not getting any support), just don't mark it.
The reason why you are marking an enemy is that you do not want that enemy to attack an ally of yours. The abilties to punish enemies that misbehave is not meant to deal more damage. I agree that it may be frustrating if they never trigger. If you want them to trigger, you and your allies have to give enemies good reason for enemies you mark to attack your allies. Your allies have to be softer targets and/or be a great enough threat that the enemy wants to attack them in spite of your mark. Your pumping up your defender abilities just makes it more difficult for marked enemies to attack anyone but you.
Ty to all for reply and suggests
Hi to all mates. I’m in trouble with the attack granted by my marking ability, because my DM attack always me. Ok, I’m a defender, so it’s correct...but I have many feats that enhanced my "Challenge attack", like Staggering Challenge, Devoted Challenge and Mobile challenge. It’s hard for a defender to use his "marking attack" if his role is to take always enemie’s blows and DM litterally do that. Ty for suggests
There are some good suggestions here. Also, if your DM doesn't ever provoke your Combat Challenge, stand next to the wizard or other ranged attacker. They'll be safe beside you, lobbing fireballs and the like.
Finally, if your DM doesn't ever provoke your combat challenge, retrain those Feats! He's basically giving you free feats. All of those feats are there to make your Combat Challenge more threatening and effective. If it is already so "theatening" that NO ONE will risk it, you can get other fun feats to use.