As explained to you here…
…the bundle is clear that you select six gems and you will randomly receive one of those.
The chest’s description says…
When used, select six 5-Star Bound Legendary Gems (Quality 2). One of the six gems will be randomly selected.
It’s in no way misleading.
Why would you expect to receive six gems when the description literally says one of the six gems on it?
You got exactly what was advertised, i.e. one of the six gems you selected.
They’re not misrepresenting anything.
This is entirely due to you not reading what you’re buying.
They don’t need an excuse for you not reading what you’re buying and getting upset because you got what was advertised rather than what you thought you’d get.