Joseline Hernandez and Stevie J are playing a shell game with their child, hiding their daughter from the court ... this according to the guardian appointed to protect the kid.

Joseline and Stevie are knee-deep in a nasty custody war, and the judge appointed a guardian to protect their 10-month-old daughter, Bonnie Bella.

The guardian just filed legal docs, obtained by TMZ, claiming she has repeatedly asked Joseline and Stevie to tell her where the kid was, but she's been stonewalled.

The guardian says on Sept. 24 she demanded that the parents produce Bonnie Bella at a specific location, but they were all no-shows.

And the guardian says, on the same day, Joseline was supposed to appear in traffic court but blew that off as well. The guardian says she's worried about the child.

One other wrinkle ... the guardian says the kid may be with Joseline in Miami, which would be a violation of the court order not to take the child outside Fulton County.

A judge just ordered Joseline and Stevie to fork over the kid ... or else.