Hello @ghaid,
I am sorry for your trouble. Are you trying to refund from the backend? The issue might be related to a conflict. Have you checked for a conflict yet? If not, kindly disable other plugins and check. If that doesn’t help then switch your theme to a default one and try again. If you are still having trouble then feel free to submit a ticket from the contact form of our official website. Our support team will check your site and help you resolve this.
Best Regards,