In 2018, Calling All Mixels was removed from app stores. However, it is still playable with Bluestacks, an Android emulator for PC. Follow the instructions in this post from the Mixels Wiki to install: https://mixels.fandom.com/wiki/User_blog:CMRdaawesomeguy/Didn%27t_get_a_chance_to_play_CAM_or_MR%3F_Now_you_can!