NOT WILLING TO PAY

I phoned the call centre in April to cancel my contract and was told that it will be cancelled at the end of May and my last deduction will be at the end of May. Now in June I received a statement which says I will be billed with R295.76 for which I do not know what it is for and it is way above my normal monthly instalment. Can someone fix this because I am not prepared to pay this money as I am expecting that my contract has ended and was advised by one of your agents that I will not be paying anything after May and the contract will cease to exist so why am I still being billed for services which I never consumed. You have recorded phone calls so listen to them and take it up with the agent concerned because I will not be paying for this.