Regions Auto Parts Sent defective engine been in fire and locked up Tampa, Florida

I purchased used 7.3 diesel engine 2001 from this company.  They claimed engine completely checked out and had 41,900 miles on it.  Upon arrival of shipment to certified diesel repair shop,  the mechanic called me said that the engine appeared to have been in fire due to hoses melted and valve cover gaskets crusted up and dented.  They attempted to put in the engine as well as take my parts of my old engine to test and found that the motor was locked up.  Mind you now out the cost of mechanic's labor charges. Contacted Region's was told that my mechanic had to provide proof of his analysis which he did.  Region's told me to ship engine back with I did and would refund my money.  Two weeks went by no credit to my credit card thus contacted Region's and they said did receive my engine and were waiting on accounting to issue back credit but due to holidays they were out.  I then contacted the accounting department after the holidays and they wanted proof of return of merchandise educated them already spoke to salesman that confirmed they had the engine.  She said would research my info and call me back she didnt so I called her again.  She said would be issuing me and refund and fax me the confirmation which I receive a day later less $1080 claiming I had to pay the reshipping charge of $490 which was orginally $150 to me so dont understand that charge and also restocking fee of 20% which was $590 on a defective engine.  No where in warranty do they say have to pay restocking fee on a defective engine.  This is outrageous.  Contacted accounting department refused to credit me my money claiming that engine was in good working order.  What the heck why would I ship back an engine that was functional vs having now go buy a new engine.  I have now contacted my credit card company to dispute their charges and the better business bureau.  I would like to warn all buyers to stay away from this company.  What a way to start a New Year huh?