I've been using
Undercover Tourist for ages and they have always offered fantastic service. E-tickets are non-refundable, however physical tickets can obtain a refund. Just select physical ticket at checkout, and they will mail you the cards within a week. Within 24 hours of purchase they will also e-mail you the ticket numbers so you can enter them into
MDE and start making your park reservations. Rakuten also offers 1% cash back on all Undercover Tourist purchases!