how to delete downloaded songs from iphone - storage does not get free

[cc8922]

I downloaded some songs to have them offline available too. As my storage capacity is not huge i wanted to delte some of the songs to have space again for others. BUT: if i switch the downloaded switch back again, the app asks me if i want to delete the downloads, but nevertheless the storage does not change! so it seems that only the connection is removed but the songs still stored on my iphone: how can i remove them completely?

Thanks for the help.