Yeah they don't last long, I recently bought a clone and made a rebuildable atomizer/drip trip with my local Vape Shop but before I was using an Itaste MVP2 Mod and a Protank Mini (2 or 3?) as well as a Kangertech Aerotank --> THE coils don't last long! You may also have gotten a bad batch of the coils because they are mass manufactured in China and shipped over and those companies strictly don't care as much as you'd think.
You're best bet would be going with lighter liquids (avoiding darker liquids/cinnamon based flavors; as these will eat up your coil's wick so fast). Try it out, turn the Watts to 9.5 and run it around 3.8 Voltage --> and make sure you saturate the coils by pulsing the tank a few times before you take any drags (you probably already do). Reason I say this is I forgot to pulse and took one drag after replacing the coil and the rest of my hits were all burned, got no flavor. So if you do it by mistake, you'll .... the coil up ;/.