You can definitely ask them.  They've done it before but I do not know their current stance on the matter.

IIrc someone else on the forums did the same thing a few months ago, and support did , eventually, undo it for them after a polite request from the player explaining their mistake.

Good to know might give it a try then.

The way it is presented I have almost done this as well. They need to change the system to redeem shards for maud. 

I thought they had?  In at least that it asked if you were sure you wanted to exchange after clicking the button the initial time.