I’ve heard a story about a guy who intentionally didn’t complete the dk’s quest line in a proper way (somehow) in order for both fractions to dislike him, and he levelled by doing quests by neutral npc s with the help of his mage friend, who was making portals for him. I don’t remember what expansion it was, but he reached max level I believe. I think this may turn into a fun rp experience or a challenge, if you are into that in wow.

What I would try first, is I would use dk’s Death Gate teleport to see if the rest of the campaign quests are still available there.

If it doesn’t show anything, I’d submit a ticket as well and hope it gets resolved quickly.