I'm pretty sure you can check also the data usage. I have no prepaid account but look around.

I’ve looked under every tab in the web portal, including “Phone Services → Usage Summary” and “Phone Services → Usage History”. These only show call and text usage, not data.

Also “pretty sure” and “look around” are completely unhelpful. Why did you even bother replying if you don’t know the answer to my question?

Well I know the answer, but because you were rude I am not going to tell you.

When in self serve and you go Phone Services > Usage Summary or Usage History, what do you see exactly?

Can you post a screen shot?