After posting a WTB for a couple of VV3's to replace dying ones & only getting one reply, I went a bought 2 (not 1, but 2) Innokin iTaste SVD 2.0 Stainless Steel 20W VV/VW from HealthCabin. I got them in the mail today (yippieeeee!), but the screen doesn't work on either of them. The unit turns on, & I can vape with it, but nothing on the screen. Is there a trick to this? Did I mess it up? Help!