Thanks.
I looked at products on your site and the image zoom is working for me, although not exactly the same as our demo.
I think this is because you are using a plugin called WooSwipe which is taking control over the image gallery & zoom functions.
If you deactivate the WooSwipe plugin, does it work correctly?
The images are quite slow to load in the zoom window too, so it is possible that may be affecting it for you. Some of the full size images are approx 3MB-4MB so that is something you could look at.