When you link your PDGA number to your UDisc account, a verification email is sent to your PDGA.com account email address. Make sure you are checking the correct email. Using this email is necessary to verify that the PDGA number is actually yours. 

To check what email you used for your PDGA account, navigate to PDGA.com and sign into your account. Then click My Account and Edit. You will see the email associated with your account there.