At Anthrocon 2009, I was commissioned by a fellow named "Eshkey" for a badge. After taking his description, and telling him the price, he said he was going to run to the ATM and get the cash. I told him that was fine, (this was my mistake, as my policy is usually to take payment in advance).
I was very busy during the first couple of hours on Friday, and sold all available slots for the weekend. Each of my customers (including him) was informed that their work would be completed by Sunday morning at the con at the latest, and they were free to come to my table any time and check on progress.
Eshkey's badge was completed on Saturday night and was waiting for him Sunday morning when the dealer's room opened. Although I was not at the table for the entire day on Sunday, my husband ran the table and gave all of my other customers their badges. Everything was picked up except Eshkey's badge.
I PM'd Eshkey at his FA account ( http://www.furaffinity.net/user/menos ) on both July 9th and 29th. I informed him of the badge being completed on time, and let him know that he was marked as not paid. I offered to scan a sample of the badge, and let him know that I'd like to complete the transaction and get his badge to him. He did not reply either time, but the PMs had been read, and his account still showed activity.
On August 26th, I PM'd him on FA and sent an e-mail to his gmail letting him know I had been trying to contact him and had gotten no reply. He has since read the PM and has activity on his account, but is not replying.
At this point, I would even accept a "I saw the badge completed on your table and hated it and didn't want to pay you" e-mail. Ignoring me is so much more rude.
I know that it is completely my fault for trusting him and not demanding payment up front. I will definitely not make the mistake again. If anyone else is approached by Eshkey (aka Menos) for a commission, I suggest getting payment immediately, or you may never hear from him again.