Although these services exist in the marketplace, it doesn’t make them legal. Automated engagement services (e.g., liking, commenting, and following) is strictly against Instagram’s API and terms of service. Instagram’s API and terms of service states, “Don’t use the Instagram platform to replicate or attempt to replace the functionality or essential user experiences of Instagram.com or any of Instagram’s apps” (Instagram, 2018).
Instagram. (2018). Platform Policy. Retrieved from: https://www.instagram.com/about/legal/terms/api/