The FSIN is calling for a review of the Indian Residential School settlement, saying the process caused more emotional damage to the survivors.
It blames what it calls, unscrupulous lawyers, jurisdictional issues, incorrect deadline dates and administrative flaws.
Chief Bobby Cameron believes the private hearings caused more damage and is calling for a review of the process, the destruction of evidence and an audit of the decisions made by adjudicators.
"This was to be a healing process, a healing journey but it actually for most of the survivors it turned out to be a horror story,” he said.
Cameron says the IAP problems have caused more emotional damage to the survivor, even though it was set up so survivors wouldn't have to go through a traumatic episode telling their story.
"This is coming from the voices of our survivors - ones who have felt that they've been mistreated, the unfair process that they went through only enhanced or highlighted the many years of abuse in the residential school," he said.
The FSIN is particularly critical of the Independent Assessment process where survivors told their stories of abuse privately to an independent adjudicator.
The IAP was available from 2007 until 2012.
Damages were paid to the victims based on the level of abuse suffered, and thousands of cases were settled through this process.