Spotify will use my mobile data plan even thouth I disabled it!

[hyzteric]

I have set mobile download off. 

I synched my playlists while on wifi.

But during the last three weeks Spotify has downloaded more than 200MB on my data plan! I use it about 30 minutes every week day in my car.

Where does that come from?

I only have a 500MB data plan per month and I don't intend to upgrade.

Moto x play - Android 6.0.1