Right, but did you mention specifically that the company announced publicly that they're supposed to support the Optimus S? Was the tech support guy totally clueless about it, or was it a premature announcement?
It's worth noting that the article you linked to is not an official press release, so the company could always say that the list of supported phones was not official either. But what is more likely is that support is being phased in, and that the list of phones you mentioned is what they're starting with over a certain period of time. Here's the part of the article that makes me think this:
"FreedomPop is gradually adding support for the 500 or so phones that currently run on its network. It’s starting with about 10 of the most popular devices that are either already or soon will be free of Sprint contracts, including the HTC Evo 3D and Evo 4G, the Samsung Galaxy S III, Epic 4G and Epic 4G Touch and the LG Optimus S."