3M car service nonsense

Took my vehicle to 3M car service in 391 Bohlmann street Hermanstad, Pretoria in March for it t be fixed since it was liking water at not moving because it was said that oil and water have mixed. In their mechanical term they said it hid top. It is a registered company and promised that their work its good. Was given invoice for R34k and said that for car to be fixed they will need R15k deposit of which i did pay without hesitation. After few days they said the car its fixed and they have added something on the invoice and had to pay R23k of which i also paid without any trouble. When i took the car it was drivable bt it was cutting along the way @nd had lot of smoke coming out of the exhaust. On the invoice it was said that faulty things were. Air filtermass meter faulty, tarpet cover breather faulty, brake shuddering. Problem is after i paid R38k yje car its still cutting while driving and when i take it bck to mechanic 3M car service they say i must now get a new or used engine because the engine its damaged and it cannot be fixed. Not satisfied with service i paid R38k for nothing.