Hmm. You’re emphasizing complete, but let’s first get some definitions down so we’re not talking a different language or at cross purposes. That happens a lot between believers.
What do you mean by Christ’s church and complete apostasy as opposed to apostasy?
This is the definition I’m talking about: http://machaut.uchicago.edu/?resource=Webster%27s&word=apostasy&use1913=on&use1828=on
Here’s the LDS definition which is somewhat similar: http://eom.byu.edu/index.php/Apostasy