Verizon FIOS & Wireless Data Overage Charges are not right and all we get is excuses Nationwide

I was a Cablevision customer for 10+ years and decided to switch to FIOS. Since we've been a Verizon Wireless customer for 15+ years putting all phones, TV and data under one company made sense.  However, I feel we are being screwed over by the joint Verizon companies and they each blame the other with excuses but no real resolutions.  I am somewhat technical but not at level to discount all the excuses that are being thrown at me.

In December 2016, both of our sons came home from college and stayed in primarily for a full 5 weeks, studying and assumed they were using the FIOS Wireless Router.  They began complaining that their connections were being dropped often and then suddenly we were getting messages from VZW that we were over our 24 gb data. HOW?  If we are in the house using the Wi-Fi network they provided. We have 5 phones on our data plan and we have gone as far as to shut off the data, uninstall apps that use a lot of data and are very conscious each time we use the phones because for 3+ months now our data useage  is getting higher and higher.  Meanwhile, both boys are using the wi fi at school so they say we are not using data.

We have been to the local Verizon wireless to complain at least 3 times in the past 3 months and were told to switch our phones to "data assist" off to see if that helped.

I did a speedtest with and w/out the Verizon network and the speed tests were terrible.  In fact, the VZW speedtest gave the following message on most of the speedtest "Uh Oh Let's see what we can do to get you better speeds."  The download speed has been at 40.43 and upload 41.94.  The VZW reps almost did not believe me that their own message was "UH OH".  We pulled in an ethernet cable and got slightlly better speed test results but not at the level of the service that I am paying for which is 150/50.  FIOS said "well if your wi fi is weak while in your house, it is going to pull from your cell plan data useage".  HOW IS THIS POSSIBLE?  Why is the wi fi not working up to the speed you sell it to me at?  Now my overage data charges are passing very high dollar amounts.

I was asked "are you aware you have two networks on your router: one for 5G and for 2.?ghz.?" However, you sell me a 5G internet but don't bother to ask if any of my equipment can work on a 5G network?  The router is in the lower level of the home, not a basement and it has been there for 20+ years, and we never had serious issues with Cablevision.  I would move the router, if that would definetly solve the problem but I doubt that is the full answer.

My major complaint is that my wireless bill is increasing at alarming rates because we are using too much data (while in our own home with a Verizon Wi Fi).  Today I attempted to get both customer service departments (FIOS & VZW) on the phone together so they can figure out what is wrong and then eventually to issue a credit to me for all the data overage.  I have had several reps at FIOS state that they agree something does not make sense and they can't understand why our wi fi would not support our devices and only use Verizon Data.   Today, I had the VZW rep tell me the equipment he saw connected and as I have been told recently, they are seeing equipment that we don't own such as a kindle on our network.  All i get is 'Oh really" then suddenly it gets glossed over in conversation.  

Verizon Wireless (VZW) said they would not close the case and issue a credit, as it will be assumed the issue was resolved until FIOS makes a visit to my home tomorrow to see if they can fix the issues.

I honestly feel we are getting to the level where a Class Action Lawsuit is going to be necessary because the consumers are being ripped off financially with one excuse after another and finger pointing within its own organization.