Honestly, I've had enough bad experiences with artwork commissions that I wouldn't trust any artist who doesn't accept payment via a neutral arbiter such as what they have with Fiverr.
While that site's a little bit hit-or-miss in terms of how the commissioned person will perform and behave, I have had some positive experience with their arbitration team where they seem to do a good job judging who it is that wasn't holding up to their end of the contract properly and rewarding the money on dispute accordingly. It's about the only reason I got my money back when an artist refused to listen to what I was telling him about the commission and just kept drawing his own thing that wasn't even close to what I was asking for.
(Basically the way these neutral arbiters work is you pay the full commission in advance to the neutral party and they hold it until the work is complete to the satisfaction of the commissioner. If the product is delivered and accepted by the commissioner, the money is paid automatically. If there is a dispute, the parties are encouraged to resolve it among themselves but if that's impossible then arbitration can be called in to settle the matter. In the case of the misbehaving artist I mentioned, I believe he got his account banned since he was so clearly in the wrong on that one. I mean, I understand that the first couple images he gave me looked amazing, it's just that I was asking for something very specific and he was not delivering the specific thing I asked for and was not even trying to ask the clarifying questions to understand, and then wound up just delivering a line-art that looked like a child's drawing that looked sort of like what I was asking for but of course that quality was unacceptable.)
