It's possible you turned off the display. I might go to a vape shop for aid, or watch some YouTube reviews on the device, most of them are good as far as learning to use your equipment. I do that with most new things I get, because sometimes a picture is worth a thousand words, etc.
If you can't get the display to show, you may need to warranty it if it's a display/electrical issue, but I am not 100% sure it's that yet, and I don't think you are either.
Best of luck,
Anna