Is it wrong to revel in karmic retribution vs. a corporation?

Earlier this year, my wife (who doesn't work, so spent my money) got me an IPod I didn't want from Walmart. Anyhoo, I called someone in their help dept. who said I could return it in 90 days. I waited 37 days to bring it in and they wouldn't take it back -- even for store credit. Some technicality with Apple products. Turned out I only had 30 days. Well, I sold it on ebay and took a $20 loss. Today, a Walmart clerk mis-scanned a product and I made $20. I think she did it on purpose, for other reasons, or didn't care. Anyway, now is everything right in the universe with this issue?