Lost mount on - check yours

CHECK YOUR MOUNTS you got last week.
Last week, 18.09, I got a Blazing Drake mount and with it I got Emerald Drake (achievement: Awake the Drake) and then Heavenly Azure Serpent (Lord of the Reigns). So they were 299 and 300 correspondingly.
On Monday 21.09 I noticed Blazing Drake and Emerald Drake were missing (though not Heavenly, but I assume it is because on the weekend I got more mounts).
Support keeps saying (I am reopening with 3rd ticket now, EU73762410 ) they don’t see anything in the logs.
I can’t check logs myself (API removed this function), like a year ago.
But I have seen many bugs with transmog and so on, so I assume something wrong happening with databases(the transmog bug implies there were 2 DB active same time last week), so I want the GM investigate further than logs they have now (which is probably new database).

Even more, another person irl was present and saw the mount and two achievements (I showed him, because it is always nice to get 2 in a row). So I am not dreaming or delusional (which GMs kinda imply by the fact that they do not investigate it properly).

Now, dear community, does anyone has idea what to do? Recommendation for me or GM? As well upvote this topic(Game Masters - what good are they?), because my issue by now is with neglecting my problem (just confirming my problem) GMs.

Me who haven’t gotten any new mounts since heroic curve :

Well the whole summer and September doing DD with 5-6 characters a week (making it 2.5-3 hours). Plus, long ago on Pandaria we did 4 ppl runs.
My main (the druid) haven’t got a drop mount since… ever.
My alt mage got ALL 8.3 mount except Anh-de (that one I got via my brand new monk which I made for heritage armor).
I am very inactive player with low progress last addons, but drake and drake serpent mounts are my weak spot.