Dismantle and disarmed auto parts

The worst auto repair in 25 Hamba Gahle Road Boksburg East Rand ever in the world....iam in need of your help just bought a new engine worked and handled by oasis auto but instead my car tend into a s**** now they don't want to refund us as their services is poor and i dont want to work with them any more they confiscated my previous engine as we did not pay them all the money...as we needed to see their work,on top of that we did not get any quotations from them prior fixing my car as we busy asked them where told that even if we can call all source won't get our money....my concern it that already the car is not in good condition so because of them hence I don't trust them any longer....messed up by crocks that act legit