Hope you don't mind us answering in English. We understand your confusion, but we can assure you that the Student Discount is available in Spain.
When you sign up for the Student Discount, it can take a while until your student information is verified, which is why you might've been charged the regular Premium price instead of the discount.
This can also happen if you didn't complete the Student Discount signup flow all the way to the end and re-entered your payment details. We suggest that you try again by opening this link in an incognito window, and preferably using a desktop, and make sure you do all the steps. You don't have to worry about getting charged twice here.
Let us know how it goes 🙂