Though you are entitled to play as you wish, some might question your choices, and why it matters,however I fully understand how frustrating it is having game blocks to further progress.
Others have made similar enquiries recently,and there hasn't been much response,partly because there is so little traffic here these days.
I seem to remember a suggestion that they had appeared in bank offers but you have take into consideration the truthfulness of anything written here.
Even if this is true, it isn't going to be helpful to you, if it was a one off event, or,if on going, you,with your game play,qualify for such an offer.
As the game changes, as does what is in the bank offers, you might just have to live in hope of buying the shards you need.