Im tired of taking it back

I am disgusted at autohouse vryheid workman ship on my bakki since brand new it has been back more times than i can count. The last time it has been back because the diff lock is not working so i book it in for 3jan 2020. (I stay 80km from town. So its a special trip everytime) i have the bakki there at 7:30 in the morning so i can get it done as fast as possible i am a farmer and i use my bakkie every day i get my bakki back at 14:00 after they come back from lunch. (I ask myself why couldnt i have it at 13:00 before they went on lunch nobody was working on it in lunch time anyway.) I had sent my driver and told him to show them the hand brake also has a problem which he has showed them before on services aswell. They told my driver they just fixing the difflock because i didnt say the handbrak. My question is if the bakkie is under warrenty and you can see the handbrake is broken why do you have to told to fix it? If that handbake fails and somebody can proove its because its a factory fault or isuzu fault who is going to pay? And to is the 13th jan 2020 guess what i come to put the difflock on and it DOES NOT work again i dont even know why im suprised. What must i do to get it fixed properly who is going to pay my down time, who is going to pay my time to take it to autohouse vryheid and who is going to pay my traveling costs.isuzu south africa just keeps you runing round and round in circles till you tired. This my 8th isuzu bakkie and my 1st new one but its been the first with so many problems