I lost 6 gold collectible cards to unfinished set

I tought that too, but I lost mine. And it has been a quite annoying that in the support chat they tells it's a part of the game that you lose all the cards if you have them in the set. And yet I remember that you have got your cards back before and I tested with that gold players to gold collectible-set.

But thanks for the answer I try to contact on twitter, but I hope that those are not the same guys that who are in the support chat, because I have done that road before.