Hi,
After a lot of in-game tickets sent about this topic I’m heading here now as a last resort.
Here’s a brief summary of what happened to my rogue:
- leveled up to 25 pre p2 patch
- did the quest “The Horn of Xelthos”
- went back to IF and waited for a mail with the rune in it
- nothing happened, didn’t expect much and logged out
- next day, still no rune so I reached out to support
- after 2 days I received a reply that indicated that I might have missed something so I ran all the way back to SFK and went through the steps of the quest again, but couldn’t obtain any of the quest items anymore as the quest was already completed
- filed another ticket, waited for another 2 days, got a reply that they couldn’t do anything about it
- filed another ticket - this time asking to reset the quest (as this resolved another issue I had in classic wotlk before). Waited for another 2 days, received another ticket response that nothing could be done
So basically as it is right now there seems no way that this rogue might obtain the Deadly Brew rune. Given that this is a key rune it seems I won’t be able to continue playing with this rogue 
Is this a known bug to others and being looked into? Anyone else experienced this? Maybe even resolved this?