Got both PMs - thanks.
Tested the following:
Registered and selected the $300 annual subscription plan (enabled a dummy gateway to test and removed it after).
After submitting the registration form, I received the email confirmation email just fine.
After clicking on the confirmation link in the email I received I was asked to pay.
So far also looks good.
After paying, I did not receive the CB Welcoming email - which might be a bug (will investigate).
You can as a work-around fill-in the Email workflow texts areas in your paid plans to have CBSubs send these after payment emails - yours are currently empty, so no emails are sent.