The way duelling works is in transaction history it always says you sent the prize pool of a duel rather than what you lost so there is no glitch in that.
What I assume happened is you didn't do /spec before re-launching the game and sometimes your tori doesn't disappear from the server the second you leave, thus by a lucky chance Shockay might have entered the duel the moment you left and that way got your TC.
I reckon you could attempt to fill a report, but I doubt you will get a refund since all the evidence shows that you lost duel to Shockay and you got no proof showing otherwise. (DC still counts as losing)