Spotify Plus to Premium

[sorenone]

Hi everyone!. Now I have a Spotify Plus subscription. That means that I just don´t have comercials when I´m listening music, but I can´t select songs in my cell as I do in my PC. I´d like to upgrade to a Premium account to do that, but I´ve just paid (today) my Plus subscription (4.99€). The price of a Premium service is 9.99€ in my country (Spain). I´d like to know if I will be charged twice or I should wait to the next month to upgrade. I don´t want to lose that 4.99€ and pay other 9.99€ the same day :S. Thank you!