no ethics

Bought second hand motor installed it, had a knock. Took it out, returned it and basically the same story. Took vehicle with second motor to their workshop. After elaborate time was told motor is fine, can can collect. Funny enough the mechanic that finalized the car was inadequately schooled to connect the power idling jet. Thus the engine wouldn't idle. I have taken the car in good faith but if everything goes wrong, we were told 30 day warranty on start-up. When we wanted to collect the warranty they told us there is no warranty.