Didn't receive Arena Rewards

[Rhasimir-1573]

There is also a sticky by Blizzard about this:

@Aelathera

Did not get Arena rewards?
When an Arena run is forced to retire due to special limited time events (like Wildfest, or the Blizzcon special arena cards), the rewards are put directly into your collection when the run is retired. The opening of the chest is a purely visual thing.

The previous forum’s post about this situation was a bit more descriptive, here is a link for your convenience:

Hearthstone Forums