The Pituitary Foundation has apologised to two volunteers who were criticised by the charity after complaining about the way it treated them.
But Jon Danzig and Joanna Lane dismissed the apology, which was posted on the charity's website, as inadequate.
Last month, Danzig, who suffers from the pituitary-related condition acromegaly, said the Bristol-based foundation had abused him in emails to supporters after he used the charity's online forum to challenge an assertion made by a member of the charity's medical committee.
Lane, a member of the charity, added a comment to the online version of Third Sector's story claiming the foundation had told her to stop wasting its time when she urged it to promote greater awareness of pituitary damage caused by head injuries.
The charity apologised for any distress it "may have inadvertently caused" and said it was "troubled" that Danzig and Lane had felt the need to go to the media. "In any charity, difficult decisions must be made in relation to the allocation of resources and the causes that they are able to champion," says the apology. "This can inevitably lead to some members being disappointed."
The apology was "doublespeak", Danzig said. "My distress wasn't as a result of decisions taken by the charity, but of the way they made untrue and unkind statements about me, telling volunteers, staff and doctors to avoid talking to me," he said.
Lane said the apology contained no admission of guilt from the charity nor any promise to change its behaviour.
The foundation's solicitor said it would be inappropriate to comment further while the parties' legal teams were trying to resolve these issues. "The apology was made in good faith with the hope of moving forward in resolving these matters," she added.