How long has it been since you added them to your account? Have you called Verizon to verify that they are on your account property? They’ll be able to tell you whether you need to input the number from the SIM, but my guess is that you don’t since you’d have been prompted for that when you added the cameras to your account.
Class 10 SD cards, formatted in the cameras? (I’m thinking that answer is yes because you’ve done this before.)
You’ll probably want to call tech support on this unless there are some additional suggestions. 770-582-0004 9 AM - 6 PM Eastern M-F.