FYI there's a good telegram group for Robosats - t.me/robosats. The website says they're switched to SimpleX, but it seems most people are still using Telegram. There's some activity on SimpleX as well though.

I haven't seen anything from Reckless Satoshi, the developer of Robosats, in a long time. I wonder if he's "retired".

I've never had anyone suggest moving to another platform. Email is famously insecure. What kind of fiat payments were they using, to not want to use the secure chat?