Peter Rowley, a comedy partner of James, also claimed the documentary contained inaccuracies.
He said: "If the taxpayer has to front up with $2.4 million to make a movie full of lies then I object!"
Others defended the drama, which attracted 733,010 viewers on TVOne last Sunday.
Matt Elliott, author of Billy T: The Life and Times of Billy T James, said: "It was a risky production because it attempted to show something other than the smiling, giggling Billy.
"That wasn't the Billy that people knew and loved. The other Billy, the offstage Billy, was a complex character."
Simmering tensions have existed for years over James's legacy, with Lynn taking on Sony in a legal battle last year.
A second screen depiction of the comedian - the cinema release Billy T: Te Movie - last week hit the top of the New Zealand Box Office, with $263,000 in sales in its first week.
But Cherie also targeted angry comments at that production, and its director Ian Mune.
Mune responded with a comment on Facebook: "The important thing, for me, is that Cherie, and you, have spoken out. After twenty years, thank God!"
Cherie responded: "Ian, what the f***? I feel your top comment is completely grotesque, offensive, hurtful and potentially slanderous. You're talking about people's lives here and I find [ ... ] your statement and its inference about what could have gone in our family completely F*****!
"And enough of this f***** myth of who really knew him. Did I? You bet your arse I did."
Last year, Cherie announced she and Lynn were considering legal action for royalties from DVD sales estimated to be worth $3m.
Sony Music Entertainment released The Comic Genius of Billy T James before Christmas 2008 and sold more than 100,000 copies, making it one of New Zealand's best-selling DVDs.
Sony believed it had obtained the rights to use film and sound tracks in an agreement with the Billy T. James Family Trust, which has administered the comedian's affairs since his death.
But Lynn challenged Sony's claim to the rights and is seeking royalties and damages.