Southdale Post office poor service

I went to Southdale Post office to renew my Car license disc on the 06/11/2020 i was helped by Sasha Ferreira she told me i have some outstanding infringements that are blocking my renewal i have to pay those fines first she printed out the proof she gave and i paid the fine for R370.00 she also wrote for me in the print out the amount I'm supposed to be paying for my license disc renewal which was R456.00. My problem is when i went to the same branch again Southdale Post office on the 12 November 2020 to do the license renewal the lady Thembikile Mayisela she charged me R504.00 instead of R456.00 and i was like the sms they've sent me doesn't say R504.00 it says R456.00 and she says there's no car that pays R456.00 or less but on the license disc renewal print out it's written R456.00?? How possible is that? And i had paid all my fines please i need my R48.00 refund. I've sent them two emails they haven't rep**** me.