How long must I wait to get my faulty Exhaust Sensor fitted

Most disappointment I have ever experienced as to visiting the dealership 3 times, on 2 occasions spending half a day, to rectify the exhaust sensor and faulty fitting. Obviously one does not get to see the Dealer principal, but mostly staff at the workshop etc, promising to repair fault, with many different excuses, the last being parts not ordered at all, at my last visit to the workshop management. Never again will I support or have any dealings with this company. Fortunately my wife had R400 000 ready to purchase a GAC, which I made her refund the money back to the bank, stopping her from almost purchasing the vehicle. Hopefully others have not endured the same treatment or promises. Does the Dealer principal hide away rather then attend to complaints?