Home Loan Settlement Ripe Off

I recently sold my house which was bonded with STD Bank. The bond amount was settled plus quite a bit extra. When I got paid out I was paid less R17 000 by the Bank. I queried it, only to be told that it was a penalty because STD Bank was not given their full 90 days notice. I find that completely ludicrous! How can I be charged such a huge amount of money because the bond was settled a month too early. That is not small money and considering I have been paying them R10 000pm interest on the bond for a few years, that too me is just *******. They will always find a way to get more money out of people no matter what!! The lady on the phone said all I can do is complain so I am complaining!!!