Unidentified Dyes - missing/gone
As you even said, the dyes system changed with April Feature Pack but I see you got refunded. Maybe you better try a personalized assistance through Customer Support, I haven’t heard anyone having this issue recently.
As shadow suggests, you need to contact Customer Support for an individualized response.
There’s no reason for dyes to go missing from your account: there’s no mechanic that would have removed items and refund dyes would have added to your stash, not subtracted. While you are waiting for Support to respond, I recommend using the search feature on each character’s inventory and your bank. If you have a personal guild bank, also check there.
I already used the search feature on all character’s inventories and my bank. I even scoured the collectibles tab in case they added them to collectibles.
Thank you both for the responses.