Car Service

I've taken a car for a major service and they refused to cover everything that is supposed to be done for 20 000 km. I've been paying for nothing all this time because the only thing they cover is oil and oil filter then why do i have to have insurance that does not assist? They are running away from covering major services. This is the second they are disappointing me. The first they never informed that I need to add kms in my plan and they didn't cover for my 105 km service I had to pay myself but they were deducting instalments.