You can use either Paypal, ATM, Credit Card or Bank Transfer if you are in Portugal and Paypal, Credit Card and Bank Transfer if you are in Spain. Be aware that an order paid by bank transfer may take up to 48 hours to be confirmed. Thus, in order to speed up the proccess, we strongly recommend you to send a proof of payment by email to firstname.lastname@example.org.
Prepay Credits are like reloadable Prepaid Cards. You charge it with the value you want and use it to make orders. See more information here
Login in Delnext's website and click in “My Account” in the upper right corner. Then go to the tab “My Credits” and click in “buy now”. It'll instantly appear the bank details to where you must transfer the money. Once you have transferred the money, don't forget to send the payment receipt to email@example.com.
Once you get in your account the credits you have purchased, in your next orders, when choosing the payment method, you'll be able to use your credits. That value will then be deducted from your account.