Most state consumer fraud divisions have online complaint forms available, and Rhode Island does.
If a business gets one or two complaints there may be a quick check. But when a number of consumers complain about a business, the division may do a far more in depth inspection.
A complaint does not guarantee your issue solved, but it is free and it is one more weapon in the arsenal against sellers who don't deliver what they promise.
Of course the best weapon is Fauna because then readers who are prospective purchasers have the option of never having to deal with this hassle and possible fraud in the first place, but if you have been waiting on a refund forever, please consider the complaint process:
http://www.riag.ri.gov/ConsumerProtection/About.php