over charged

On the 30th of November 2015. Telkom debited my account for 741.24 as to debiting my last debit of 299. To my understanding they have made an error in their billings. Prior to my contract coming to an end I had approximately 3-4 calls from consultants offering me new contracts. I declined as I would rather save my money instead of spending it. I made my call to telkom and spoke to a consultant requesting for info as to why I was overcharged? She said that I had taken a new contract which I did not as mentioned above regarding my decision to decline any new contracts. A case was logged (***7). I even had an sms to confirm that I will be credited the amount owing to me. Today I spoke to Ayabulela and he said that telkom is not going to reimburse me as the contract has expired and in order to avoid further charges I must take out a new contract. He advised that I should sign cancellation form to which non of the other consultants advised me on as they were under the impression that I should be reimbursed. There is a major lack of communication with regards to info passed on to me and I feel I should get my money back as to what they owe me. As a consumer this is unfair. Help me