Telkom *******

I have contract with telkom ,when i sign it it was a Febuary special for 30G for 199 per month but now its no longer 30 G per month its 10 G they email statement every month its shows it 10 G not 30 G that i sign for.i tried many times to call them but they can't answer my calls and i emailed to them they don't respond and i think they knew about this .