Well, Mr. Duck, I feel your pain (really). A couple of comments … Generally, at least in the USA, pre-paid plans receive very little (if any) support – from any of the carriers. What you are experiencing is not unique to Verizon. While this is overly simplistic, the carriers dedicate support resources (highest to lowest) this way: (1) large business accts, (2) other business accts, (3) personal post-paid accts, (4) pre-paid accts. And, #4 is a good way below #3.
About the equipment: Verizon’s “real” profit center is their network. Indeed, much of the hardware they sell is a loss-leader. They sell it to get customers to pay for the use of their infrastructure. (That’s not to say VZW does not make a profit on some hardware – it does.) And, with regard to your comment “does not actively support these devices,” You have a point there. The carriers may offer some support of devices they sell but can one really expect support for a device with which they are not familiar? This is not a “Peplink issue” at all, in my experience.
No idea. What plan is/was it? Was it intended for use by routers/hot-spots?
There are a lot of smart folks who have shared many experiences here on the Forum. Spend some time reading and ask incisive questions as needed.
Final comment: The “mobile data situation” in the USA is a total mess. It’s super-expensive, difficult to provision and just “make work.” Sounds like you are figuring that out – sadly. It’s not about the hardware you’ve chosen.