Let’s agree to disagree then, because my point is that they were just called “flatrate”. I even just found this article describing “the first flatrates”, which also just calls it “flatrate” without any qualifier throughout the article, but makes it clear from the beginning that a flatrate is, in itself, unlimited: https://www.netzwelt.de/news/76329-verkehrte-netzwelt-erste-...

Finally, I remember the “Alkohol-Flatrates” that came up in clubs a few years later (and were, unsurprisingly, soon outlawed). Their point was that you could get a theoretically unlimited amount of drinks for your cover charge of typically 15DM or so. In practice that’s a stupid idea of course. I tried it once at the behest of a coworker: The drinks were atrocious, the floor was covered in a thick grime of “free drinks” and the crowd consisted of the type of people who would be attracted to an “alcohol flatrate” in the first place.