I did the same collection dance to pull this off and spent about $40 on packs just to also receive a duplicate. I also spent in game gold before realizing this bug existed. I feel scammed out of my money now AND the in-game gold I’ve been saving that now feels wasted on this.
Between that and the sole focus on Darkmoon Treasures, it really seems not worth it to spend on this game anymore. Every little thing is about extracting extra money out of us without any care for what their players actually desire to purchase.