Hello there,
never does mistakes.
You can just fix that problem yourself just by locking the top curvature of the AirPods into the hollow curvature of your ears by just pushing the AirPods backwards into the hollow curvature of your ears after inserting them casually. After locking it there, it never falls out unless you remove it by pulling it forward and outward.
Hope you understand and try it once. I bet you would never blame for anything.
Cheers.
You don't know what you're talking about. Go back to your cubicle.