Problems with pof renegade plus - POF USA Renegade Upper Receiver

I sent in the Renegade Plus because of issues of it running extremely dirty. I had to pay For shipping Then they told me that nothing was wrong with it And they're sending it back. Told them what the problem was They said they guarantee that it will cycle ammo not how clean it will. After 80 rounds without a suppressor it look like it had a thousand rounds through it. I own a piston gun Maybe they should stick with those. In the future because of their worthless customer service I would never give them a dime again.