Ford refuses to take responsibility

I took my Ford Ranger XLT to Daly Ford Potchefstroom for a service, service took two days Friday the car came back Saturday the car wouldn’t start at all. Daly Ford had not even put oil in my car, I report the issue they claim my car had an oil leak, the car I drove from Mthatha in the Eastern Cape to Carletonville in Gauteng. I took the case to Ford National and Ford National promised to take my case to Daly Ford Potchefsroom. They did but they chose to side with their franchise. Here is the story, my car had an oil leak some time ago and it was fixed but the engine not washed, it was driven from Mthatha to Carltonville without any problem, on the 30th of October I sent it for service to this Daly Ford, first it took 2 days to be serviced with brakes, I paid my R7 000 without any qualms, we took it back to the house in Carltonville and parked it for 1 night, when time comes to go it doesn’t start we found out they forgot to fill the oil. Now they refuse to take responsibility, yet there’s a proof of that, my oil from eastern Cape didn’t leak out, my oil after finding out that they failed didn’t leak only theirs can’t stay, be the judge of whole ford people if they can all agree on this stupid assessment. If anybody has strength to take up my case please.