+1
Oooh!!! We doing this anime style now, finally!!! Huehue... I totally support this, but on the concept of "cancelling" the request, probably might not be the suitable idea... I mean, imagine if the farmer was about halfway done and still has ample time to finish the order but then the client cancels the request, that'd be a disappointment and other farmers might not take up on some quests due to bogus clients... So, if you were to put up an order, you should be clear enough and pay in advance (to the NPC) and just collect the reimbursed tokens back when the quest/order expires (as suggested, a week)...
And since we're talking about anime, remember, Log Horizon. ?