My world has disappeared

My world is called: "MineVille 4".
Sunday, September 23, 2018 was the last time I played in the world.
On Friday, September 28, 2018 I opened Minecraft to play in the world but it does not appear in my list of worlds.
The world weighs around 100mb (maybe a little bit less or more).
I do not know what could have caused the error, but I'm totally sure I did not delete it.
My Xbox gamertag is LB Cheetah11.
Please, if you need more information, I will be willing to say everything I know about the world.
You would make me very happy if you give me back my "MineVille 4" world, even if it is a backup I will accept it. Thank you