Deal with the bandits quest help?

Okay so currently im doing the deal with the bandits quest and decided to help instead of kill. After that i happen to get 3 new quest which is to help them, get their rival and i can get the resistance,hp and mana increase. My problem is when i tried to do it with a friend, after my friend died when the quest popped up. The only words available was goodbye and i changed my mind and the oak's rival and the other rivals were greyed out. Can you please help me on this? Do i have to do it with a friend that has not done the quest yet? Sidenote: my friend has already finished the quest long time ago.

If your friend already killed the bandit, he can't be in the camp when you choose to help.
If your friend already helped the bandit, and you choose to kill it, you and your friend will become enemies - he will not be able to help kill the bandit.

Basically,you have to do the bandit quests alone or with people who made or are making the same choice.

So means i have to do with a person that is also doing the quest at the same time. And not someone who has already completed it?

yes, or on your own.

Your friend can help you kill any bandit as long as he didn't help that bandit. If he helped that bandit, he can't help you kill it.

thanks guys that really helped. oh well i guess i`ll make a new account then :)