From what I got from someone commenting/translating over on another site, the artist feels that the way the plotline/development was going was deviating too much from what their collaborator (the actual creator/owner of the Ouga Saki character) intended her to be, so they're cancelling the series.
And now it looks like the artist may be rebooting the series. The translator there doesn't know if it will just be redoing the artwork so that it's a different, non-copyrighted "gyaru" or a whole new plot, but either way...