INCORRECT DEDUCTION MADE FROM MY BANK ACCOUNT

I bought an Explorer in August 2016 (The price log) therefore my 2 year contract with Multichoice ended on the 27th of August. During the month of August I made a few calls to Multichoice wanting to know how much my last instalment which is debited on the 2nd of each month will be by the 2nd of September 2018. I got different amounts from different agents that I spoke to. Due to these conflicting amounts I decided to call them again on the 1st of this month in the afternoon. This time I did not speak to an agent but opted for the option that says the amount due can be emailed to me. @ 16:50 same day I got an SMS saying that the amount that will be debited from my account is R475.00. In my bank account I had an amount of R 610.63 left therefore the R475.00 would have gone through without a problem. Yesterday I go to my internet banking profile only to find that Multichoice has debited my account with an amount of R 640.46 hence I was now overdrawn. This morning I check my bank again and find out that the R640.46 has been unpaid by my bank and I have been charged a R60.00 fee for the unpaid debit order. I have never ever had an unpaid debit order on my account. This has now resulted in my banking profile affected as well as my ITC status. Multichoice is responsible for this mess therefore they have to pay this fee. They were aware of the contract end date, as their loyal client they should have advised me correctly and also state why the amount will be R640.46. They should not ray to debit my account again. I will sort out the payment once they have taken care of the unpaid item fee charged by my bank.