The Prosperity Gospel promises healing.

So what happens when someone gets ill, is promised that God will heal them, but doesn’t get better?

Does this put a dent in the theology of the Prosperity Gospel?

Absolutely not!

According to Costi Hinn (a former insider, but now a vigorous critic, of the Prosperity Gospel), the following reasons apply in such cases:

• ​Making a negative confession: using negative words about your physical condition would hinder your healing.
• Hanging around negative people: allowing the negative words of others about your physical condition would hinder your healing.
• Not having enough faith: not believing or giving enough money to prove your trust that God would heal you.
• Touching the Lord’s anointed: speaking against or opposing a man of God who is anointed.

(Hinn, Costi W. God, Greed, and the (Prosperity) Gospel (pp. 49-50). Zondervan. Kindle Edition, emphasis added)

So, there you go.  The Prosperity Gospel and those who peddle it are untouched by blame.  The fault lies elsewhere – with those who are negative, or associate with negative people, lack sufficient faith, or dare to speak out against ‘the Lord’s anointed’.