I am currently using an iPhone on Speakout's data network, something that I am probably not meant to do.

There is nothing in the terms and conditions published by SpeakOut that prohibits you from using an iPhone. They merely state:

Examples of prohibited uses include, without limitation, the following: (i) continuous mobile to mobile or mobile to landline voice calls; (ii) automated text or picture messaging to another mobile device or email address(s); (iii) uploading, downloading or streaming of audio or video programming or games; (iv) server devices or host computer applications, including, but not limited to, Web camera posts or broadcasts, automatic data feeds, automated machine-to-machine connections or peer-to-peer (P2P) file sharing; or (v) as a substitute or backup for private lines or dedicated data connections. This means, by way of example only, that checking email, surfing the Internet, downloading legally acquired songs, and/or visiting corporate intranets is permitted, but downloading movies using P2P file sharing services and/or redirecting television signals for viewing on laptops is prohibited.