Just beat him. Its not that hard.

Just did this quest at 70 on a draenei warrior, and gained 1g89s from Beat Bartleby, 3g75s from Bartleby's Mug. Followup is back to the normal amount of silver you'd expect from a level 10 quest at 70, though. :(

I somehow forgot to do this quest, and walking by the tavern at level 50 I spotted the yellow exclamation mark on my minimap. I went in and one shot him, then turned in the quest for 3500 exp. Woah.

I never did this quest on my Warrior, ran past when going training on my level 57 (yes, missed training at 56), slapped Bartleby in the face, took his mug, handed it in, this awarded me:
2200 + 4350, aka 6550 xp for doing:
1. Press with mouse,
2. Press auto attack
3. Press with mouse
4. Move 2 feet
5. Press with mouse
6. ???????
7. Profit.

I was surprised to see Bartleby pop up on my minimap while picking up Deadmines and Stockades quests on my 20 draenei warrior. I went ahead and did the quest and the rest of the chain, but now I'm curious if you can do the previous quests.

i want to beat him but the guards alwais kill me

This quest is moronic. Despite the fact that Bartleby isn't flagged, fighting him will flag you. This is an undesirable outcome for anyone who plays on a PvE server to avoid such ninja-flags.

Um... i failed this one, and now i can't do the quest again...

""Beat Bartleby""? Damn that's one Quest Giver who's got the right idea!