So, I was at Aether Paradise Pokémon Center to buy some crap and heal my Pokémon, but I saved in the Pokémon Center and I ate lunch. I finished and turned on my 3DS, I was still in the Center but I was unable to move and my character was not there. What the d*rn?
Have you ever used any cheat tool? More specifically; an early version of PKHex?
Apparently, the early version of the PKHex tool has created similar symptoms to what you are referring to.
It’s possible to reverse this damage, according to Desu Oshawott, who said that the editor allows users to change their locations to circumvent the bug. The most recent version of PKHex has corrected the issue, Kurt said.
https://www.polygon.com/2016/11/22/13717194/pokemon-sun-and-moon-save-glitch
If you've never used a cheat tool, comment and I'll see if there's a different answer. And if possible show screenshots.