Did the same, and the stupid thing about this is that the companion version saber is labelled as a Cartel Market platinum, so it is incredibly easy to fall foul of this. I didn't spend vast sums of credits on the saber though I can see first hand how easy it is to do so. How this wasn't picked up prior to the patch is beyond me.
It would be very poor form to not do the bare minimum of returning lost credits to those who raise the issue in a ticket. I've sent a ticket and messaged Eric, I'm not holding my breath for a refund but if you don't ask you dont get.