Sigh. I told you that I would get something wrong, and that someone would correct me. I did, and they did, and it wasn't a small thing, either.
I wrote: "you can't do multi-party audio calls with the basic version - or even text chats, for that matter!". As the CTO of SightSpeed has pointed out to me, that doesn't read correctly at all for what I was trying to say. Of course SightSpeed has text chats in their basic version. What I was trying to say was that you can't do multi-party text chats in the basic version, just as you can't do multi-party audio calls.