I bought an Engine from ROJAN on Friday 7 April, it was installed in the car on the Sunday 9 April

I bought an Engine from ROJAN on Friday 7 April, it was installed in the car on the Sunday 9 April. It is not working, I have reported to ROJAN but they are giving me hard times. I cannot lose Tewnty Seven Thousand five Hundred Rands for a damaged engine. Can they please sort this problem out.