Faulty engine

I went to Wannenburgs to buy an engine for my Isuzu Frontier because the current engine in my vehicle cost me about R45000 due to a *********. I explained to Louis the manager that i want an engine for my Isuzu which is in perfect condition. He sold a 3.0 engine to me and said that its in perfect condition and he knows the engine and that it doesnt need any work. I was for 2mweeks without a vehicle while Manie who does Wannenburgs work for them did the engine exchange. I was amazed to find out that Louis bought another engine for spares to do a conversion on the engine to fit in our vehicle. The conversion was a mess and the vehicle is heavy on diesel and the timing gears is totaly warn. I went to see Louis today because weve got a month engine exchange. He refuse to exchange or repair the vehicle