Expired Contract

I've been a client for Telkom Mobile for years back when it was still called 8ta. My contract expired before and I was told if I don't fill out a cancellation form and submit it at nearest shop my contract will not be cancelled and in fact it will turn into a month to month and I will be built the same amount I had been paying for.I have had my last and latest contract for R 117 per month and even thou numerous attempts of trying to upgrade I was turned down because if being unemployed.even thou I have been paying all these contracts being unemployed and have not missed a payment for 3 years . I decided to leave my contract and not cancel it as I would not be able to get another contract elsewhere.I understood that I will be charged my normal R117 till I request a cancellation by filling out the cancellation form.Today I received my statement via email and was confused due to different amount on it.i called in.i was told me that if I don't cancel my contract after 25th month I will be charged the normal amount for the contract which included extra fees amounting to R 488.57 per month. I am still confused as No Where in the terms and agreements does it say this!! Day light *******