As has to be pointed out over and over again until it gets through the thick skulls of people like you "unlimited" meant that you have unlimited data restricted by rate.
I was offered 15mbs, that is 15 mega bits per second unlimited I asked if I would use my connection 24/7, which is different that just have access to your system 24/7 under any contract. . X seconds in a in an hour (3600) time hours in a day (24) times days in a year (356) = 461,376,000 Mb a year / 8 for MB = 57,672,000MB / 12 to get monthly limit = 4,806,000 MB / 1,048,576 to get TB = 4.5TB month
time arguments come from people have no real clue, AOL and other used to charge us by the hour of connection. Users took up time on a single modem port blocking other users, and @ 28.8Kbs (later 56.6Kbs max unachievable by FCC rules) limited how much data someone could download in the time alloted. Then people started offering unlimited, but did not worry about caps because you were limited by modem speeds. This was the start of rated unlimited access with no caps. When broad band, my first was Road Runner, we had unlimited at a rate, as how much data could you possibility download, there was not much out there, plus they were competing with AOL. Today they keep the same type of contracts but complain because the ISP's never upgraded their back ends and now have problems providing what they offer. If we had true competition in Broad band internet we would not see this, it would be like the old AOL fight.
We can do a car analogy, you have unlimited highway rights limited by rate. You can drive on the highway all you want, as long as you restrict yourself to posted speed limit.