False information by Vodacom

I received a phone call from Vodacom in November stating that my contract was ending and would I be interested in upgrading, I immediately said no I am not interested. Then the person said that would I be interested in doing the top up every month after my contract has ended. It would only cost me R160 (odd) for R230 airtime. That would be the only fee. The person proceeded to say that I would pay my last installment in November and from December I would pay the reduced rate. To my horror I received an invoice from Vodacom this morning with my full installment plus R149.99 for a "contract upgrade". I did not upgrade, I was under the impression, which was falsely given by the call agent, that the amount would only be charged after the contract ended and I would get an extra R30 airtime. Surely it is ******* to provide false information to the public and to create false expectations.