You can file a dispute for any of the following reasons:

• Unauthorized activity in your PayPal account (a payment you don't recognize or are confident you didn't authorize).
• Issues with your purchase (a purchase doesn’t arrive or match the seller’s description).
• Issues with the seller (a seller is not cooperating and doesn’t respond to your messages, or you're simply unable to reach an agreement).
• Billing errors or issues with automatic payments (you've been charged more than once).

Timeframes for filing a dispute:

• Item Not Received: Dispute must be opened within 180 days of the date you sent the payment to the seller.
• Significantly Not as Described: Dispute must be opened within 30 days of the date of delivery or fulfillment (as applicable) of an order or within 180 days of the date you sent the payment to the seller, whichever is sooner.
• Unauthorized transactions: You must notify us of a problem with the transaction within 13 months after the payment was made.
• Unexpected billing agreement payment: You must notify us of a problem with the transaction within 8 weeks after the payment was made.
• Incorrect payment: You must notify us of a problem with the transaction within 13 months after the payment was made.

You can read more about our various policies in the PayPal User Agreement.