Extremely Bad service

My Corsa Utility bakkie is in for a fault with difficulty with starting. It’s been 2 month’s now and after trying to fix the computer box it did the same. Then they replaced the computer box with a new one and still the same problem exist. After a week they send the bakkie to test the diesel pump, now a week later they still don’t know anything and after speaking to the Service manager Jakkie, he told me that he is to busy to work on it and I have to speak to the service advisor Stella van der Merwe. I have complained with the Manager Piet Botha several times and all he says is he will have a look at it and come back to me. But in the meantime I have to wait for my vehicle.