"Seppo is usually ridiculously busy running his business. Sales and support of the RFD900 are only a tiny part of RFDesign, mostly he's doing complex hardware design work for other companies.

So he definitely responds to warranty issues and the like…"

"The +++ mustn't have <enter> after it, but the AT commands need it! Did you change your serial console settings back after you got into AT mode?"

"First, check that you aren't already in command mode - "AT<enter>" will do it. If you get "OK" then you're already in command mode (but that's probably unlikely.)
Next, check that communication is working properly - the simplest way to do this is to…"

"This is a basic RF theory question, nothing specific to the RFD900.
You need to calculate a link budget; there's plenty of information available online, and there's even a calculator I found with little effort…"