online software purchases

[den51]

In 5 years, and many online purchases of software, I've never had any problem till now. I ordered poker playing, [instruction], software after reading Jim McManus' account of his play and winning the World Series of Poker, in his book "Positively Fifth Street." He recommended the software in his book after winning nearly a quarter million dollars as an amateur at the WSOP, and I'm an avid amateur player myself.

I ordered at playsmarterpoker.com not knowing I could get the software directly at the creator's site for the same price, and for free shipping. When my order had not been confirmed on the first follwing business day, I cancelled it. I was contacted immediately by the admin of the site, and he asked if there was anything he could do to "make/save the sale." I said yes, you can ship free, and give me 15% off. He agreed to $10 off, [$89.00 software], and free shipping, in writing!
It's been well over 30 days, and he hasn't honored his agreement by crediting my card, and he's not responded to any email inquiries.

I'd like to have input on the most effective way to not only get the word out on this guy, but also get my $15 back. Thanks for reading.