Business ProfileforPrefer Auto Parts

Purchased a used engine for a 2009 Cadillac CTS 3.6l from Prefer Auto Parts. I was told by a sales associate named ****** they had 3 in stock to choose from, one with 54K miles $1985, 47K for $2075, and 31K for $2200, with 6 months warranty and purchased the 31K at $2200. An engine was shipped 2 days later from ******************** where it was purchased for $1600 including shipping, which was verified by **** at ******************** with only 30 days warranty and NO verified mileage on the engine. The engine I received has excessive mileage on it (approx. 150K miles) with a dead cylinder (#5) and verifiable compression check of 36 to 42 lbs. on the remaining 5 cylinders. Basically, what was shipped is nothing more than a junk/core engine with zero value. Contacted the Owner of Prefer Auto Parts at ************** which told me it was only 90 days warranty regardless of what ****** told me and that she had been fired for misleading customers with false information and there was absolutely nothing he could do but would have an associate contact me. Next day was contacted and offered $150 for my inconvenience which was declined and explained legal action would be taken. I sent the Owner multiple photos showing the internal problems this engine has. The following day the Owner contacted me offering me $400 for my inconvenience and legal action would be a waste of time an effort. I requested a copy of the original sales invoice/contract which when received stated no verified mileage for the purchase amount. Then after contacting the Owner again, he attempts to offer me a replacement engine which he claims only has 71K miles on it at his cost of $1845 shipped. At this point to me it's obvious he trying to keep from any legal action to take place and is attempting to get out from under this original sale completely. Because the original engine shipped has been verified to be junk it has never been installed but remains sitting on a pallet. Where do I go from here?