I was on like level 6 when the app crashed and made me log back in. I put all the same info but it took me back to level 1 and everything was lost. When I sign on and off it will only revert back to the new one. It made me make a new username and everything. Any ideas on how I can get my other progress back?
Are you sure you used the same account you used last time? If you are very positive about this, then I would recommend contacting the Pokemon-Go support at https://support.pokemongo.nianticlabs.com.