This question is literately one of the only reasons I joined this site.
One day, I was just doing wonder trades on Alpha Sapphire. I got tired of repeatedly
getting Pidgeys, so I decided to go ahead and get another entry in my Pokedex: Porygon2. I traded my Porygon to my X via GTS, and so I switched to my X game, and Porygon evolved normally. Then, I wanted to send Porygon2 back to Alpha Sapphire, so I went ahead and used Pokebank and put Porygon2 in. I switched back to Alpha Sapphire, and tried getting into Pokebank. It said I hadn't progressed in the game and had to pass the point where I got a Pokedex. I had completed the game and beat the Elite 4 three times, so I wondered what was up. Corrupted data, that's what! All my work, after 687+ hours I put into the game, gone. 671 Pokedex Entries, gone. Every single Legendary and Myhical, most shiny, gone. After all that work, I almost wanted to cry. And, I'll admit, I did shed a tear or two. Most of my Pokemon were shiny, with perfect EV's, and now their dead. I've spent weeks trying to find a solution, and the only ones I could find were to delete the data, which is the last thing I'm gonna do.
This is either the Pidgeys fault, or Porygon is a hacker. What I think happened, is that while wonder trading, one Pokemon contained a hack. Is this what happened? Also, is there a way to fix this?
R.I.P Alpha Sapphire