Maya 2017 - Vector Displacement map not working (from mudbox)

[Auzie123]

I am having some issues with Vector Displacement maps. The stages in which I done it were:

1. Imported mesh from maya into mudbox
2. Sculpted the mesh on a separate layer
3. Extracted the texture maps (32 bit EXR, 2k resolution)
4. Created the setup in the hypershade maya.
5. Imported the displacement exr into the vector displacement node.
6. Render and play around with the scale to get it correct.

I have gone through multiple websites to see other peoples settings and I can't seem to figure out what is wrong!? One issue I am having is with the iterations, I can't seem to get them above 5 without maya either taking extremely long to render it or it just crashing. If I ever get anywhere with the displacement it seems to look 'cracked' and completely out of shape. I have attached a few of the images. I hope someone can help I would really appreciate some professional advice!