SARS code 3702 not being taxed

Good day. I have codes 3701 and 3702 on my IRP5. I claim more then the SARS rate due to the fact that our rate includes fuel, maintenance, capital, insurance and depreciation. I was told by SARS the employer is not taxing the 3702 reimbursement. I now owe SARS. How do one correct such a scenario not to owe monies at assessment. Thank you
Regards

Do you keep a logbook?

Yes logbook with open and close kilometers and official kilometers has been kept.

Then you can enter the travel allowance section on the tax return and claim the business mileage there by completing the section.