The point that I raised originally - that it's the Captain's call - really makes writing an email to customer service, or trying to "make sure it doesn't happen again", a waste of time and energy.
Most flight crew fly standby when they are commuting, or going on holiday; and when a flight is full and there are no more flights that day and they want to get to their destination - well, they know the deal, and they hope that their fellow staff are kind enough to let them board. So don't expect any change in policy.
Moreover, non rev passengers only use jump seats when no other seats in any cabin are available (hence the OP's inability to move to another seat - because there wasn't any).