Using google maps on Apple

I’ve just started a new job as a courier driving I was using Apple Maps for the job at first but every time I went out of the courier app to navigate to the job the sat nav would revert back to walk even though I had set it to drive. As you can imagine having to press drive 140 times a day was annoying. So I decided to get google maps now all of a sudden after a month it will not let me use google maps and I was happy with it and wanted it as it was hate the way it worked for a month now it doesn’t !!!!