Isuzu being let down by staff

Took my ISUZU for a service that cost me R4900. Only to find out afterwards that they didn't replace all i was charged for. I questioned the technician first, he denied my aligation. I have been a qualified ISUZU technician at a dealership myself. So I went to Wayde. Was treated a bit cold when i told him about my suspicions in a respectful manner, no one likes to hear that their employees are not doing their job properly, i can understand. Especially when you are responsible for them. It was inspected and in front of me, and I was correct, I was charged for something that wasn't replaced, and wouldn't have been for another 105 000km. That would most certainly have caused major part failure in the future at my expense. He did apologize for his technicians blunder. When asked what could be done to make me happy, they wouldn't do better than a R600 discount on labor. That is a insult. And charging me no labor for the next service isn't good enough either. I will certainly not recommend them to anyone in the future. If i think about how many of my family, friends and clients i help put in either a ISUZU, OPEL CHEV AND SUBARU.