The Word of Faith/Prosperity "Gospel" is heresy. They preach a different gospel not only for mostly holding to Oneness theology ("Modalism" aka: Anti-Trinity), but also for being the most popular purveyor of the gospel with their Word of Faith preaching which is heterodox and destructive on so many levels. I didn't understand the depth of the deception until I heard this series from Justin Peters "Call for Discernment" series.
A Biblical Critique of the Word of Faith Movement
Part 1: Health and Wealth or Prosperity Gospel
Part 2: Mangled Manifestations
Part 3: The Hurt of Healing