Songs stopping after two seconds and skipping

[Ako009]

I have Spotify premium and listen to songs offline while in the car, my iPhone is connected via a USB cable and played fine until a few weeks ago, now songs stop after two seconds and then Apple Music starts playing. When listening to a playlist and skipping a few songs Spotify then starts to skip on it's own after playing the first 5 seconds of the song, the only way I've found of stopping this is to unplug the phone and plug it back in which is becoming really annoying! I've tried changing the stream quality and cross fade and I think I'm out of options..
Does anyone know of any other things that I could try?