YES!!! I have used up 33% in 5 days of my 40 data!!! Each money it is getting worse. I had a mobile hotspot and used 20 gb sometime a few more. Since Cantina I have used 30 up in 15 days. I went to 40 used it up in no time. Then I went to 60 and still used up the data before month was out!!! I have spent almost $2000 dollars in 4 months. I am calling them and telling them to come get it Nothing has changed except I haven't even watched horse racing as I use to do with 20 GB. Rip offs !!! Last phone call talked to 3 people and they all said the same thing. With no explanations.
You need to explore the connected devices and setup data monitors to expose what is consuming your data. Cross reference this data with what Verizon shares with you on the unbilled data usage reports. Confront VZW about any discrepancies between the logs from there. If you do not have any logs to review then you have no case to confront VZW with. Note that VZW will not acknowledge any personal data usage logs you create, they only acknowledge their own billing system.
Data monitors are a tool to facilitate a conversation and understand what is going on with your personal devices. As we often find out most of the time data usage problems are on the users side of the equation, VZW simply provides the internet access that is being requested. Think of a faucet that has been left on in your home versus the water utility. The utility company is going to keep sending you water (and bill you) until you turn off the faucet.
I highly recommend data monitoring tools like Glasswire for PCs. Each OS is going to have various tools and techniques to expose data usage.