The "Extra Set", doesn't this set come with a .5 and a 1.2 ohm coils? Which coil are you trying to put in when this happens, I can imagine it may be the .5. Your 150 should have no problem with a .5 ohm coil.
Go back to the place, if you didn't order it online, and try to work out the issue. There are several variables it could be and without having a different .5 atomizer or another Mod that can possibly fire the original atomizer that you are having issues with, you're dead in the water. Would be nice to poke that Atomizer/Coil into an ohm-meter to see what it is reading. Also if you had a multimeter to see if there is even continuity - that's another variable - is this atomizer working in the first place?