Bug in captial city? or othes concern?

Sorry, bad English here, from Hong Kong.

Since I granted a level 40 Roman civ city, and started to build the capital city building.

When I built an "arena", the game bugged out, every button was unclickable, and finally, the black screen went back to the desktop.

When logging in again, the "arena" did not appear in the city, and the blueprint disappeared.

Further, I want to know what is happening, so I fold my "empire point store" into blueprint, the destruction animation is done, then no blueprint turns back.

How can I bring those blueprints back to progress the quest, since I am stuck there, and I cannot abandon the quest?