Grenfell Tower families have accused corporations of having "amnesia" during the public inquiry into the fire.
Bereaved families told a report private companies and public authorities had answered "I don't recall" a lot during the first phase of the inquiry.
One respondent to the report by charity Inquest said it was a "disrespectful" approach with a "lack of candour" to those who had been affected.
Seventy two people were killed in the tower block fire on 14 June 2017.
The council, the tower's tenant management organisation, the police and the fire service were all quizzed during the inquiry's first phase.
Companies involved in Grenfell's refurbishment also provided statements.
Fifty five families contributed to the charity's report.
One respondent said: "We all have lapses in memory. The bereaved and families from our side who went up to give evidence had an extraordinary level of recollection.
"In comparison the corporate entities had an amnesia fix. The chair should have been stronger to say, 'you have to try and recall'."
Another said: "It feels like certain people are being let off the hook, not being asked important questions. Now the first phase is finished. We don't feel satisfied."
The families have criticised the informal way their lawyers could raise questions they wanted asked of witnesses with the inquiry counsel - by passing them post-it notes.
An interim report was due to be released by the inquiry in spring but the Grenfell community has been given no firm date yet.
The families said they wanted an independent panel to be put in place before hearings resume next year, a venue layout that kept families at the centre of proceedings and the government to help workers attend the inquiry without losing their annual leave.
Inquest also identified "outrage and exasperation" that interim safety recommendations suggested by lawyers representing the families had so far failed to be implemented.
These included abandoning the "stay-put" policy for buildings of more than 10 storeys, and ensuring each London borough had an aerial ladder.
In its most recent update, the inquiry said chairman Sir Martin Moore-Bick was "considering the range of suggestions made by expert witnesses and legal representatives".
Councillor Elizabeth Campbell, leader of Kensington and Chelsea Council, said: "It is a tragedy that must never happen again, whatever it takes and whatever the consequences for all authorities.
"We will not be defensive, we are a public authority, and we want the clear and unvarnished truth for the victims and the bereaved."