Post Office Highveld Centurion Poor Service

I visited the post office this afternoon around 15:30 to renew my car licence and received very poor service from the lady at the teller. My car licence was R384, the handling fee for the post office to process the transaction is R72 (in total of R456, I paid R500), and the change owing to me was R44. The lady had not given my change. And when I called in several times to let her know of her mistake, I received no answer from this branch. Not only must we (the customer) pay a high fee for the licence disc but also get looted of our change. I had provided my phone number on the form in order to pay my licence. No return calls to say I forgot my change.