Just a short version, but yes. Next time please research what you buy. There is no possible way for you to use LTE on your current device in Europe unless you perform a rather difficult hardware mod.

Your best bet, flash 4.4.4 factory image and erase everything, sell it on Swappa or eBay (highly recommend Swappa though) and then take your small loss, and purchase an international version. Best of luck.
Team Inferno (Co-admin)