Rewardport.com Deceitful Company and Non-responsive Customer Service Internet

I have been doing business with this company for several years. I cashed out three times for a $10 Amazon gift card with no problems; however, I cashed out a $25 dollar Amazon card back in June 2012 and have not received it as of May 2013. This is my first report on a company because I don't want others to end up in the same situation as I have read several reports online about the same thing happening to other people as well. 

One thing that particularly bothers me is the unresponsive customer service. I have sent them numerous (very courteous) emails asking about the redemption. I have received absolutely no response. Since I have been sending out emails since October 2012, I would think that it would give them an ample amount of time to respond. I just want to warn others to avoid wasting time with this company and allowing them to make money off of your time without giving any back to you.