really disappointed in the communication levels towards client

My mother and I bought a car from this dealership and the wires were looking like there was rats chewing on them. They had guaranteed us that it will not be a problem. In addition, to mention that even when we bought the car the engine light was on already. After a month and a couple of weeks we went back to them about the engine light hence we were going to have a trip with the vehicle. They told us that we can go on our trip and come back they will look into it. We did exactly that, next thing they told us that we took the car to the machenic...asking ourselves (me and mother) how can we take a car to the machenic within 2months of purchase but anyways, we mentioned hello peter and that they should rather take their car they then insisted to do something. In addition the car has been failing its dekra inspections because of the engine light. After it was checked they told us it was alright. Until recent lastweek sunday 04 Nov 2018 the car broke down on me and I had a client in the car as the car is for business, this was a great problem for my business. Further more they said that the problem is the mobiliser since the original key was lost as I have been using the spare key and that they will sort out the spare key and that was settled. They gave us a call saying that even the battery needs to be changed and the battery didn't have 6months having been bought. We proceeded with their plan and still the car didn't start and we were told we were going to get the car on Monday (yesterday) and we tried to call them back and we got other people that were not on that shift with the people assisting us until today we went there and only then they tell us it's a problem with the wires and I have lost the whole of lastweek worth of money, this week its 2days and counting.