I had to open a second ticket and got this as a reply -
I have had a chance to look over our internal documentation on this for you, and it looks like the issue with some accounts not receiving the recent WoW Twitch drops has been reported by several other players. Our QA team is currently in the process of gathering reports to look into a fix, so I went ahead and added your account info to our internal bug report. Unfortunately, we don’t have a workaround for the issue at this time or an ETA for when that fix will be ready, but I’m sure if you keep your eyes on the hotfix log and patch notes, you’ll see it mentioned before too long!
So, I guess open a ticket, and if they close the ticket with the general response, open a new ticket, and document the old one in it. I’m going to keep this one open till I get the mount.
Also side note: Be kind in your ticket! Don’t be demanding/rude.
If you want an example of what to submit, I can create one so you can copy paste.