Autopartsexpress.com They sent me the wrong part twice then defective part. Now they won't give me my money back Internet

I originally ordered one part for my car. One week later it arrived but it was the wrong part in the correct box. I took a picture of it and sent it out so they could see the mistake. They sent me the replacement part but it was the same incorrect part. When I contacted them they told me they did not understand what I was talking about. Someone later contacted me after I told them I was going to file a complaint . They then ordered a part from another distributor and this part turned out to be defective . Three weeks later I had to purchase a other part from a different company. I then used the return labels that they provided me to send the parts back to them . I got confirmation that they received the parts back on April 11,2014. It is now April 17, 2014 and they won't return my emails where I ask for my money back.