We just emailed the receipt. We only run invoices for users that request them every few weeks, as it's not a common request. Generally, the receipt from the payment gateway is enough for most. I guess I could have been more clear above that it wouldn't be an instant turn-around, and thanks for your patience.
As for the other questions, I missed seeing those altogether. For upgrading, you can check out our Upgrade Guide, which basically will tell you that you just use the Joomla installer to install the latest release, and those files will be upgraded automatically:
www.sourcecoast.com/jfbconnect/docs/upgrade-guide
You don't want to manually copy any files over. You must use the Joomla installer.
As for the profile plugins, currently, CB is all we're officially supporting as they are the only ones out with an official 1.7 release. Kunena has one as well, which we're testing with right now, but it's not as stable as we'd hope for.
Finally, we're releasing an updated version of JFBConnect later tonight or tomorrow, and you may just want to wait for that version (v3.4) to come out before upgrading.
Thanks,
Alex