bad service and having another cars computer box in the car we bought at ford amanzimtoti

We bought a Ford ranger 2014 model 2.2 used took extended warranty at ford amanzimtoti Nov 2017 but had a problem with the car where the engine stopped running in Dec 2019. we then towed it back to ford amanzimtoti where we were told the engine had shutdown because the injectors were failing to pass diesel to the engine but the cost of the new engine was too much R143, 000 which we couldn't raise. but the car was dissembled on the dashboard where the guys from ford amanzimtoti fidgeted with the computer box now when the car was towed to a reputable auto centre ( east coast auto centre 877 north coast road, redhill we were assisted by Mekesh) where the engine was fixed but had to call in an agent to programme the car he said the computer box in our car doesn't belong to our car it belongs to another car, which made us so upset because we trusted ford we need answers or Ford SA also does ***** now. We want our car to run so that we can use it we have been without a car since December 2019 now its September. I don't think ford would have taken a car from the previous owner without checking if everything was in order before they took it and sold it to us. why did they open the computer box and don't pick this up and why was the dashboard of the car opened in the first place when the problem was the engine. we are so disappointed and angry with what ford amanzimtoti did to us. We demand answers we want this problem to be fixed asap.