Why don't you just find a list with all those free premium accounts, use one, and done. It's what I did. Yeah, sure dumb names but its free. And just open %appdata% and .technic folder - the pack folder ur using so eg voltz (VOLTZ folder) and open bin folder and install it into the jar like normally, if it doesn't run/freezes etc just delete the whole modpack folder and re-select it from the site launcher. Good luck.