Verizon doesn't keep a tally of the Data usage on DSL or FiOS. You'll need a router that maintains a monthly log to record your bandwidth usage OR use software on your system to monitor your bandwidth usage (less accurate). The only thing "Verizon" that watches data usage would be "Verizon Wireless" which is a different company from Verizon, even though Verizon has roughly half ownership of Verizon Wireless. They have a Verizon Wireless portal to check data usage on a per-phone basis, and soon a per-plan basis.
I know they can run audits against lines that they feel might be abusing service, but I've not heard of them being able to give a value for data usage. Just so I'm aware, do you know where to obtain that information? I'd like to compare what Verizon has on record to what my router says.