interfering with my account

I have a account with telkom that an open line and we had an agreement if I use up the data and the calling minutes my open line limit will be zero . After two month the change the deal<br> Without consulting with me increasing g my limit to R250 and with me agree with it. I made a call and Im waiting for my minutes to run out, sow I drop the call and I get a message tellin me i have used almost R180 on my open that I don't no about. Now I suggest telkom to a lot of my friends now I'm regretting it.