Understand we don't have much to work with beyond what was stated. Shooting left could be the result of many things. The instructor could have offered up a number of solutions and coached you through, but as you stated he walked away without further assistance. If the gun is properly zeroed, hitting left, simply indicates the shot is breaking when the gun is misaligned. What causes this misalignment needs explored. You stated he "told" you that you are shooting left. Was this not apparent to you? Are you finishing flat at the break? What does the gun do in dry fire? Can you discern muzzle movement during dry fire? What distance? What target size? How far left? What is your group size? Does the issue present itself in slow fire, rapid fire, or both? Are you slapping the trigger? Staging it? Are you right or left handed?