So was the mistake due to their part (i.e. a game glitch/bug, etc) or your part (i.e. accidental fusing/selling of runes, etc)?

Cause if it was their fault, maybe they could have done something to address it, then yeah, maybe I'll agree with you that in this aspect of support, they are lacking.

However, if the fault lies in you, then I see no fault in their support here.