All transactions made through the 'BUY' button are eligible for PayPal and Depop protection. If a buyer feels as though the item they've received isn't what was advertised then they can raise a dispute with PayPal. Always hold onto any proof of postage and conversations with the buyer as these may be needed if a claim is made.
If PayPal verifies that the item isn't as described or was mis-sold then they'll most likely ask the buyer to return it to you. Once they do this and provide proof of postage, the funds will be transferred from your account back to theirs.
If PayPal verifies the item was advertised correctly then they will most likely close the claim in your favour.
If you're enquiring about a claim that has already been resolved, then the best thing is to contact PayPal directly. If you need any help with an ongoing claim then we're always here to help.