Using a new device, cannot load offline music

[user-removed]

Hello there!
I have the problem that I have loaded some offline music at my spotify account and it uses round about 2 GB on my iPhone. So my premium expired and a friend gave me his premium account so that I can use it for some days. But now if would save the same playlists as in the account which I used before, and would save them offline, I have to load every song again and spotify doesn't use the offline music which I already have. Is the music linked to my old account or why would he load it again? Is there any way to fix this problem so that I am able to hear the offline music which I already have on my device with my new premium account? I hope you understand this and help me.

Best regards,
Alex

[user-removed]

Ups the title is wrong, it has to be "Cannot load my old offline music on my new account without downloading it again"