JDM Engines Corp. JDM Engine Corp Customer Service? Refund? Math? You Lost me at hello! BUYERS BEWARE!! Internet

It is with the saddest regret that I have ever had the misfortune of dealing with JDM Engines Corp. I bought a Subaru engine from JDM Engines Corp. for ($949)
When I received the product it looked fine on the outside, so I had it installed in my vehicle. The engine ran but had a terrible knock, a cracked piston and low compression on that cylinder to be exact. Naturally I was upset having spent the money for this product, and paying to have it installed.

Never did I think that JDM Engines Corp. would not hold up to their warranty. When we contacted them about this problem they were less than friendly, but reluctantly agreed to send us a replacement only if they received the broken engine in the condition that it was sent to me. I had the engine pulled back out, put back together, and shipped back to them, and remember this at my cost ($150).
 
When they received the engine they told me that it had never been installed in my vehicle because he had pictures of it when he sent it, and it looked like it did when he sent it to us. He then informed me that I was not going to get a replacement engine, but I could pay to have the junk engine shipped back.

I finally just asked JDM Engines Corp. if I could have a refund. They seemed to be fine with giving me back my money, after they took out their 30% restocking fee.
Now here is the good part. Lets do the math and please correct me if Im wrong here
$949 30% = $664.30.
 
I was refunded ($559.30) and they told me they subtracted the 30% restocking fee from ($949). It seems their math benefits only them. When I asked them about the other $105 they told me they did not make a mistake. Then told me they could only give me $50 more and did not even hold up to their end of that deal.  

 I have never had such a headache or had to jump through so many hoops with a company to get the product I paid for in the condition that it was promised to be.   
I am out a couple thousand dollars just for having done business JDM Engines Corp.  I know a couple thousand dollars may not be much to a company like theirs but to me it is huge.  I sincerely feel bad for everyone that may contact JDM Engines Corp in the future for their services. 
I may only be one voice but I will be doing my best to forewarn others of their business tactics in future.