wiggle and reflected edges ..?

I'm not entirely clear on what's in your comp, so it's a bit hard to diagnose.  I assume you are referring to the blck edges around your comp frame?  There's a bunch of other weird looking stuff going on with your character, but I assume that's not what this post is about.

The wiggle effect you've applied is a very simple position wiggle tool.  You could apply it easily just writing an expression into the position parameter of the layer, if you're comfortable with that.  It's not sophisticated enough to extend the edges of your comp.

Some simple solutions:

Increase the scale of your layer so that the black edges are never visible.  (This may soften your overall image a bit.)

or

Duplicate your layer, and remove the wiggle effect from the lower layer so that it fills the black space. This may look a little obvious depending on the content on the edges.