What is Wrong

I for so many times order parts for my Chev Utility 1.8 in or out of Warrenty and there are never parts available or when the parts arrive it is wrong, I run a business and I always out of my Chev because we struggele to get parts I cannot blame the parts department in Somerset-West but are sick and tired of GM not deliver the service always 10 to 15 working days, my Chev was just out of warrenty, the front wheel bearing pack up, to my account and so the list go on, GM will never see me again as they CAN NOT DELIVER A SIMPLE SERVICE