As you have discovered, saving a discount with a list of Discount Codes actually spawns a whole series of separate, identical discounts, one for each code in the list. While there's no way to mass-delete discounts in Seller Admin yet (this is a wishlist item we'll probably be able to implement as a new feature at some point in the future), we can ask Development to delete them manually for you. We'd need you to tell us the part of the Discount Name which is common to all the discounts you want deleted, or we can just delete all of your discounts across the board if you prefer.
To confirm your identity and attend to this request, please email your E-junkie account password, or your Subscription ID (from your Seller Admin > Account Summary screen), or your original activation code (from the original "Account information" email we sent you at registration) to our Support team along with the details of your request:
https://www.e-junkie.com/ej/contact.php
