(iPhone 8, Samsung Galaxy 9, Macbook Pro late 2016)
(iOS 10, Android Oreo, Windows 10,etc.)
My Question or Issue
Welcome to the Spotify Community and thanks for posting about this!
Hope you don't mind me replying in English.
Since you're mentioning that you paid for Premium twice during the same month, it'd be good for you to check out this support site article.
Make sure to carefully read through the 'Do you have more than one Premium account?' section under 'More help'.
These steps should definitely help you out with finding and blocking the source of the unexpected payment.
Hope you find this useful. Keep us posted if there's anything else we can help with 🙂