Unhappy with the handling of my issue

In January I started getting phone calls from Vodacom, i just did not understand that since my contract was coming to end in the same month :why are they harassing me so I thought. Since i was on maternity i waited until April to go to Festival Mall branch where i was advised to pay(arrears) then i must wait 48 hours for the payment to reflect and then i must call Vodacom to cancel my contract of which i did. A month later i started receiving calls again, I went back as was told i must pay(arrears) wait 48 hours and call Vodacom to cancel the contract as the last one was not successful. And two days later when i called Vodacom to cancel the contract I was asked why i want to cancel the contract i gave my reasons and then the guy asked me to rather take the 49rand every month whereby i will get airtime and data. And i agreed. A month later no airtime but data, i went back to Vodacom to ask for cancellation and was told all is fine(No more 49 rand story) . Three months later Vodacom is calling me , sending statements. Someone called me and told me it is just 49rand i must just continue with it for 24 months. My question is if i have a contract with them why they have not debited the amount rather sending me statements that i owe and my account i now in arrears. What is a waiting period if indeed i took a contract, i went back a month later to tell them i want that cancelled since they did not honor the contract. I want this 49 rand story to go away soonest.