Verizon's "unlimited" data FiOS internet plans really are unlimited for most consumers; use a terabyte or three in a month, and you probably won't hear anything from the company. The vast majority of home internet users rarely approach those numbers. But the ISP has repeatedly shown that there are limits to what it'll tolerate — and customers paying hundreds of dollars every month aren't exempt.

DSLReports reveals that Verizon recently sent a warning letter to a customer who forks out $315 every month for 500Mbps FiOS speeds. Apparently the company wasn't thrilled that this user had burned through 7TB consistently over the course of several months, deeming it "excessive usage" and threatening to cut off service completely if it continued through the month of May.

Verizon has openly boasted about the freedom it gives FiOS customers

FiOS data plans are marketed as being free of the hard data caps that Comcast customers must constantly be mindful of. (The company is transparent about some restrictions on consumer plans. Running a home server can get you booted off the network, for example.) Yet here, Verizon's letter pushes this particular customer toward more expensive business-class plans "which support very high internet usage levels." Is that something regular FiOS can't do? The note also urges this user to make sure that peer-to-peer file-sharing apps (read: Bit Torrent) aren't quietly sucking up data.

By now the question you're probably asking is "what was this person doing with all that data?" Apparently "volunteer web crawling projects like Seti@Home" played a big role in the data meter running so high. For its part, Verizon would have you believe it's a bit more than that. In a statement to Ars Technica, the company outlined what 7TB looks like in simple terms.

To put this in context, FiOS Internet residential customers we have contacted would have to watch at least 6,660 movies per month or 222 movies per day to consume the amount of data they are using per month.

But unless some personal server was involved, what those network resources were used for doesn't really change the underlying problem. Verizon is advertising an unlimited plan and not holding true to the whole "unlimited" thing. The company has confirmed it's encouraging customers with an abnormally high data thirst to switch over to business plans "appropriate for their data usage."

Nowhere on the FiOS website does Verizon spell out exactly where the line is, or when taking advantage of those speedy fiber internet becomes inappropriate. It's not even in the fine print. The communication skills are also lacking; instead of an ominous letter, maybe a friendly phone call would've been a better look and helped with the whole big, bad ISP image. Obviously this person used way more data than 99 percent of Verizon's customer base, but he never ran afoul of the rules as they're currently written. Only a year ago, Verizon openly boasted that FiOS customers can use their service however they see fit.