Poor administration by Pro Admin

Property was purchased and Pro Admin Pretoria handled the levies, they calculated the levies that I had to pay and gave the amount threw to the attorneys which I paid. After a few months they realized that they made a calculation error and now they want me to pay for there mistake in calculation. <br> <br> It was their responsibility to do the calculation and if they made a mistake then it is to their own detriment and they need to write off the money.