Citroen did not follow clients instruction

Problem: requested for a service and full 360 check with Melanie (SA) .<br> A week later I was quoted for a part to be fixed for an amount f +/- R20 000 and authorized for everything to be fixed apart for the CAT Converter as advised by Marlin it was fine that vehicle drives without the Cat Converter and upon collection on the 08/09/2015 I noticed that the Dashboard lights came on and was advised in presence of Marlin that it fine to drive as is a the lights come on due to the Cat Convertor that needs to be replaced.I then picked up that the Exhaust was not fitted correctly fitted and had to go and have it fitted properly by another supplier and paid R900 additional as the dealership was closed on the week-end and vehicle is now cutting out and we took the vehicle back to Citroen Tygervalley(21/09/2015 ) and authorized for the Cat Converter to be fitted. Dealer confirmed that Citroen Head Office had one CAT Convector in stock and was then advised that the part is coming from Jhb, then authorized instead we are now told motherboard is the problem after the engineer told my husband its the CAT, MOTHERBOARD COSTING 14k after paying 16k for a 360 check of the car, ANGRY AS YELL,