Sadly I am scared they won’t extend this event for those who are a few days behind for the ‘supposedly’ anniversary special reward.
A similar post has been made in General discussion by someone sadly in the same situation as you are.
As I pointed out there, for reasons I completely fail to understand, this year they have decided to make their anniversary rewards, something not everyone will get even if they were part of that said anniversary event.
Previous years reward was handed out as long as you logged in given a a certain time frame, and was even account wide few years before.
But this year was totally different since you had to log 14/21 days to get the ‘said’ anniversary reward, while only getting a ‘chance’ at getting the other two rare rewards from within the anniversary crates.
So in the end, some wont have gotten any of those “rare” anniversary rewards even if they were around and logged in during the time of the event.
Of course they will have gotten a few extra shards and relics which will be very useful to them if they are still leveling, but not so much if they are full T4+ already (and that’s a lot of players out there)
Now as someone else said in that other thread, that mount will possibly reappear some day at some vendor, RF one or gilding one if you are lucky, but probably not in the short term.
Sorry 