I ordered a set (8) of diesel injectors in the mid...

I ordered a set (8) of diesel injectors in the middle of April. I received the injectors and installed them in my truck. I am a certified Diesel engine mechanic. After installing these injectors the engine ran far worse and had injector knock in 2 or more cylinders. I called the company and they said send them back and they will test them and replace the faulty injectors. So I sent them back and 3 weeks later I hadn t heard a word from them so I called them and they had said that they had just checked the injectors in and out them in there testing queue. Another week later I still hadn t heard and called again. They said they hadn t tested them yet. I damanded demandedif they weren t tested by the end of the day I wanted a refund. They called me back later the same day and had said they all failed testing so they were sending me 8 new injectors. I received those a week later and installed those that weekend. I found that the truck ran a little better but still had injector knock in at least 2 cylinders. I then called again and they had told me the same thing as before. Seeing as how this is a 12 hour job minimum each time it s done I decided that 2 times is enough and wanted a refund. They told me to send them back again and they would test them and issue a refund as long as they failed testing. 2 weeks later I had to call once again cause I never heard anything. They had told me that all 8 injectors had passed testing and they would issue a refund minus a 30% restocking fee cause the injectors had passed testing. I know for fact that at least 2 injectors were causing knocking and the engine to run with a lack of power. I had argued that they were faulty and they told me there was nothing they could do. Finally we came to an agreement of a 15% restocking fee and that they would send the full refund minus the 15%. They also owed me core injectors that I had sent them in the beginning. I have since received the core injectors but have not received the refund. I called and emailed after waiting 2 weeks and never got a return call or email. So I proceeded to file a dispute with the credit card company at the end of July. I just found out on September 4th that the credit card company had favored the Merchant because this company said they credited my card $69.50 on April 29th. They credit on April 29th was due to back ordered parts that I had ordered with the original order of injectors. I told them that they can keep the backordered parts and send me a credit for those and that I d find those parts on my own. I m looking for my money back that is due to me for returned parts that were advertised as something that didn t meet the standards advertised. I ve since ordered a set of (8) injectors from AC-Delco and haven t had any issues since.