Using smartlink and terminating apps

I have an issue with this and it working with my iphone.

If I use amazon music it connects fine and plays whatever i want, but how do i stop using it without touching the phone? Best I can do on the car touchscreen is seemilngly to pause playback.

Similarly with google maps, i tried it for directions and wont bother again as the car satnav is better. I can select stop directions but the maps are still displayed. I can go to radio for the rest of the journey then when i can legally touch the phone Amazon music is still live and maps are still on the screen.

Even worse is to switch to radio pull out the cable connection to the phone, and not pause the music and it is still live streaming to the phone.

The concern is obviously that i am using data and dont seem to be able to stop the apps without handling the phone?