Demo Isuzu sold with and Engine change and no spare keys

So my dad bought a Demo Isuzu at Westvaal Secunda with 10000 KM when we took the car for the first service in June we were turned back stating that the Engine number on the vehicle did not match the Original Engine that the vehicle was purchased with. Okay later the Car was serviced but it was clear that the Engine was changed and my dad was not made aware before purchasing the car. In addition the car came with no spare key and when we go to Westvaal Secunda they always promise to search for the key but they always fail. I submitted the complain with with Sonya Buitendag and her response was that there was no need to reveal the information as an Engine defect is just like any other defect and because the car is still having a warranty that is ending in 2023 then my dad should not worry. So the engine was changed and Westvaal Secunda don't see a problem at all just because of warranty, mind you my dad is planning to go on pension soon so this was probably the last vehicle he was going to buy before going on pension. Now he is stuck with a vehicle which had an Engine change and Sonya felt to remorse or obligation or whatsoever. I would never advise anyone to buy a Demo car at Werstavaal ever!!!