I have two Delta ecredits and tried using them earlier today. But when pressing the continue button at the bottom, but an error message pops up saying that "We're sorry, please select minimum 1 or maximum 5 items before proceed." I don't have a skymiles account and on the ecredits policy page, it says that up to 5 ecredits under one name can be used. I tried using them by entering them in the payment section while buying a new itinerary, but that didn't work because you need a ETK code or something and ecredits don't have them. How are you suppose to use Delta ecredits?