Members of the Mother and Baby Homes Commission have refused to appear before an Oireachtas committee for a third time.
The commission had been asked to explain comments from one of the members about how much witness testimony was included in the final report.
Last week, Professor Mary Daly told an Oxford committee that anything contained in the final report had to meet "robust legal standards" of evidence.
In a letter to the Oireachtas committee, the Commission said it's not true to claim survivor testimony was discounted.
Committee Chair, TD Kathleen Funchion, says it's disappointing the Commission members won't take questions
She said this third decline is "Another smack in the face for everybody whose trying to get genuine answers to this whole situation."
Deputy Funchion said "They have refused again, for the third time now, to come before the committee to answer any questions.
"We're really obviously annoyed, very frustrated - and I just think at this stage now, this report absolutely cannot stand and it really needs to be scrapped."
Children's Minister Roderic O'Gorman the Commission's decision is 'disappointing' and is urging them to reconsider.