BOBBI KRISTINA BLASTS Grandma-Cissy Houston ... Says Fans Shouldn’t Buy Her Book!

BOBBI KRISTINA is on a mission to make sure grandma Cissy Houston's new tell-all book crashes and burns -- by BOYCOTTING it altogether and pleading with her fans to do the same.

Cissy released a book this week called "Remembering Whitney" -- which is all about Whitney Houston's life -- and made the rounds on a slew the talk shows promoting the hell out of it.

But Bobbi wasn't too happy, tweeting to her 119,000 plus followers, "Anything concerning my grandmother's book, I and @nickgordon of course personally have nothing to with."

She continues, "I haven't read and won't ... I find it to be disrespectful to my mother and me being her daughter won't tolerate it."

FYI -- Cissy was on Oprah earlier this week (again promoting the book) and admitted her relationship with BK was strained ... and admitted she knew that Bobbi didn't want the book written.