Well, given it was both coils, I'd say it's (somewhat) unlikely to be both coils bad, although I guess it could happen. Also there may be something going on with the mod, where it's outputting incorrectly.
With that said, going with the easiest, most likely answer first, how did you prime the coil in the device? Did you let it sit a while, did you take some long, slow priming puffs without EVEN touching the fire button? Did you take a few very short puffs, given that you can't actually increase wattage on this device? So some very short pulls, with time for the coil to really soak up the liquid?
I might watch a video review on your device on YouTube to make sure you are handling everything correctly, it can sometimes be the easiest way to learn how to handle it.
If not, and you continue having trouble, I might suggest going to a brick and mortar near you to get help with your device..
But any more information you could provide would likely help someone on here help you isolate exactly what is going on, with what you are currently saying, it could be many things, including user error (the good news on the latter, that's the one most EASILY fixed, with a bit more knowledge and etc.)
Best of luck,
Anna