When can I file a dispute for a transaction?

Disputes can only be filed against a seller under the following conditions:

• At least 7 days have passed after the item was purchased
• The transaction is not rated positively
• No more than 60 days after the transaction date
• You have not yet filed a dispute for the transaction in question
  

Example:

Item purchased on September 1 (and hasn't been rated positive by the buyer)

First date to file a dispute: September 7
Last date to file a dispute: October 31