Telkom Mobile Overbill on Contracts ALMOST DOUBLE

I took out a Telkom Mobile contract in January, advertised at R249 per month. I phoned to make sure that it would NOT go over this amount. Telkom said as long as i cap it it will not. I had to pay R250 in January, which they debited from my account. I phoned again around the 31st January 1st February i filled in a cancellation, as this contract did not have a top up, which then it is pretty USELESS. 1st February, a consultant phoned me back and assured me that the contract WILL NOT GO ABOVE R249 PER MONTH AND CHANGED IT TO TOP UP. I have not received a bill from Telkom for R 423.81 THIS ISNT EVEN FOR A MONTH. The contract is R249 per month, I took this out near the end of January, and paid in R250 WHERE ON EARTH DOES THE AMOUNT COME FROM. I wanted to cancel this contract, which was within the cancellation period and they CONVINCED me to keep it. Now they are RIPPING me off