i've seen you post this a couple times now. you really need to get over this my man. loc pins were refunded because they were an item that you had and then lost.
there is no reason for the arcanes to be refunded. you still have them. they are not gone. you don't lose anything from this.
more notably the fix you refer to was from what appears to have been a typo in the costs (assuming a mistake on DE's part for the oxium/cryotic back then rather than malice). it's a completely different thing. this isn't "the costs are changing" (let alone "the costs are changing because of a mistake on our part"), it's "we are removing the cost going forward". Cetus Arcanes just went free to play.
i get that they were expensive, i have like seven or eight sets of cetus arcanes that were built before this change, but honestly... who cares? people who put in that farm have had access to the cetus arcanes for years. that's what your farm bought you. doesn't seem so bad to me.