If you have made a payment to a project and would like to request a refund, you can do by click on the "cancel" button on the projects table. But please note you can't cancel a project if it has already been completed, and amount of refund will be calculated based on the project's progress.
The amount of refund will be calculated based on the project's progress. For example, if you have paid $100 for a project and the project is 50% completed, you will get $50 refund minus by the fees. so you get the refund amount of incomplete targets of the project.