This happened to me on Chimera. I was doing the white mage relic and we failed Chimera and for some reason my quest lost all progress and I had to start over. I did place a call to support without any response. Considering that Chimera is the very first fight, I really only lost my weapon and materia so I just started over. However, someone who is at Garuda or completed Titan has invested A LOT of time in this. We play this game for fun and losing all of that hard work to start over is NOT fun. Please SE, do the right thing in this matter and restore these players' lost time and progress!