I had Spotify Free and since yesterday Premium on my cellphone.
How can I see or know that I'm a Spotify Premium Member ? on my cellphone,
because you don't have my number.
You can visit https://www.spotify.com/us/account/subscription/ and check out your premium subscription.
Did you subscribe through Spotify or your mobile carrier? If you can download music and play any song by tapping it, you have premium.