Need help for Redoran House quests

[Gilpy75]

ok so im doin quests for Sarethi and he asked me 2 find and duel Ondres Nerano, but im also in the thieves guild, and when i did Habasi's quest 2 get nerano's key...I killed him...now that hes dead i still cant end the quest, and i cant even be expelled because i killed him before i joined Redoran... and i use the Xbox GOTY version, so i cant use cheats like on the compy version...how can i possibly end this quest? i know i cant do other redoran quests and come back and figure this 1 out later, but id rather get it done. can anyone help me out?? im really confused and need a hell of alot of help! thanks every1 if u decide to help a poor gamer! (even though my character is kick ass!! u can check the description in Wepons of Mass Destruction thread)

[galraen]

You can't complete this quest unfortunately, it was permanently broken when you acquired the key (you should have got it without killing anybody). Fortunately I don't believe it's an essential quest and you can still become the big cheese in House Redoran. I have completed the HR promotions without even finding this particular quest, so I guess it's simply time to move on.

[Gilpy75]

O man thnx dude, thats awesome ( i decided 2 see wut would happen if i went werewolf with hercine's ring and kill him, nothing did, so im just gonna go do other quests) thank u soo much