for hygiene reasons, earrings are sealed in a polybag at the studio.
14 days from delivery to withdraw — only while the seal is unbroken. once the bag is opened, the right of withdrawal lapses by law (§312g II nr. 3 bgb).
write to the studio first, then send the piece back. you cover the cost of return shipping.
this does not affect your statutory warranty rights for defective items.