Flashing and debranding your phone voids your warranty so better don't tell them what you did ;) Just mention you tried to flash it with SEUS and it gone dead.
SE Tool lite is not as self-explanatory as XS++. In XS you know where to put the firmware files and the custpack without even looking at a tutorial.
In SE Tool you need to know that the MAIN and FS goes in the first tab and the custpack into the misc tab. There were lots of people who wanted to upload patches and clicked write GDFS instead of write script and killed their phones. That's why I would advice a noob to use XS++