My advice to you, for the future, would be to either take some time to observe an artist's turnover rate, or directly ask about it when commissioning them. Or even set a (reasonable) deadline.

Different artists get commissions done at different speeds, and while I know that Bewares can be posted regardless of price, getting impatient within a week on an $8 commission is REALLY, really overbearing.

Other than that, I don't have much to say that hasn't already been stated here.