I am being charged excessively and unreasonably

I hired a car from the company and they are charging me R400 for having a C10 license and hiring a code 08 car. This is grossly unfair as I have had my license for more that 24 years but still they insist. Nor I was informed upfront for this potential charge, only once they invoice they find a need to make more money out of me!!! I will never use their services neither should any of you!!