Commissioner Islandforge won't pay or communicate

WHO: Islandforge on Deviantart.com

WHERE: http://islandforge.deviantart.com/

WHAT: He ordered a commission from me for a lineart of him and his wife...Said he liked the finished product- and more than a month later hasn't paid OR responded despite being online and posting work.

WHEN: I finished and posted his commission July 21st.

PROOF: I went clearing out my inbox and naively got rid of his notes too. All I really have is the commission- and a photo he sent me for reference. The commission is here http://mousenibbles.deviantart.com/gallery/36945032#/d54i0mw. I wouldn't go through the trouble to draw something that wasn't a personal work if someone hadn't asked me to.

EXPLAIN: Islandforge commissioned me to do some lineart- not expensive at all- of him and his wife. The agreed price was 15USD, which would be delivered on delivery of commission. I sent him the image and he was happy with it- but since then he's ceased all communication, ignoring my polite notes requesting payment/reminding him.

MOOD: Unsatisfied.