They send you a completely new one. I know of exactly just one person who did it. He noticed that the mesh on the earbud itself was straight up new (his one was

They send you a completely new one. I know of exactly just one person who did it. He noticed that the mesh on the earbud itself was straight up new (his one was dented a little bit in certain spots due to his attempts to clean out some earwax using a sim-card ejection tool), and the plastic was spotless clean with no scratches.