An exclusive Malibu rehab facility has filed a claim against Casey Johnson's estate -- a claim that would wipe out all of her assets.
TMZ has obtained legal docs in which Renaissance Malibu claims Casey went to rehab there in August, 2009. Renaissance claims the $74,750 bill has not been paid.
TMZ first reported Casey's entire estate was valued at around $75,000 -- which would leave $250 if the claim is paid in full.
According to the docs, Casey spent 30 days at the facility and then received additional days of therapy.