It should have sold on ebay in a heart beat at a decent price. Recent ones sold on ebay have fetched a strong price. Given the condition I think $3500 wasn't too bad, if you could have gotten that price.
What was the minimum reserve you were looking at? Given you are new on ebay, and the two bidders are new and may have appeared as fake to some, could have scared some bidders away. You may be best consigning to an auction house.
http://www.ebay.com/itm/1930-Spaldin...p2047675.l2557