Any new Slice really needs to be charged at least overnight, despite the directions saying 1hr. Try charging, turning your machine on, and see if you can home the blade. If it is still stuck, you will definitely want to call MM. I suppose it could be a power issue since you are international and probably use a different voltage.
As for the question about PTI paper....I truly believe that the thicker the cardstock, the more you shorten your blade life. So, while you may be able to get it to cut PTI, you may run through your blade replacements much faster. Those are teeny, tiny blades.