Netnutri.com Nutrisaver on Amazon.com I returned the order, but never received a refund. They claim they never received my package. Internet

I ordered a flat iron "Chi" from Nutrisaver on Amazon.com. Two months later it stopped working. I contacted the company to ask for a replacement or a refund.
First, they made me contact the manufacturer to get the iron fixed because it was on warranty. The manufacturer told me they don't deal with regular customers, they only work with beauty salons.
I called Nutrisaver again. Finally I got an answer that they will do a refund for my order. They gave a number to call for return instructions. I called the number, the representative told me to send the product to their address and include the invoice in the package, and that was it. That is what I did.
Two weeks after I sent the package there was still no refund. I contacted Nutrisaver via e-mail. They told me that they never received the package. I was battling with customer service for weeks.
Because I don't have a tracking number for the package, they refuse to give me a refund, and simply keep telling me that they never received the package.
I wish I could do more to get my money back, but because I trusted the company (and followed the return instructions), I sent the package without tracking number, I can't do anything. I just wanted to everyone to be aware of their fraudulent business practices.