I was dealing with using the android game services and billing. It looks like there was linker issues when the nugets were released to use them. I generated a project & nuget to bridge them so I could use them with monogame in the android project.
Feel free to use them and update as well. You can find the Android Bridge repo under my github ExzileGames. Same goes for the nugets, you can search the same ExzileGames. This is a bit of contribution back to the community.