You can contact the GAD Guest Suport Team. From the FAQs:
What do I do if I never receive notification of my verification of service?
Please allow up to 2 weeks for email verification for your activity from Disney. You can log on to your account from this site to check the status of your volunteer activity as well. If you have not received any communication or seen the status of your volunteer activity change after 2 weeks, please contact the Guest Support Team for assistance. Please keep in mind that if you signed up for the program as part of a household, verification emails are sent to the lead volunteer.