Double amount debited

I have tried to reason with the Telkom LTE call centre and have been given the run around so many times I don't know where to turn to or what to do next. On the 31st of December 2015 my bank decided for some unknown reason to dishonor some of my debits and I have in the meantime managed to sort that issue out however Telkom has since debited my account my bank account on the 15th January 2016 by R632 double the amount (R316) that should be debited. Whenever I contact the call centre I am told that it takes between 7 to 14 days for my payment to reflect on their system. They also cannot pick up the payment of R316 that was deducted from my account on the 30th November 2015. Please can someone straighten this mess out as I would much rather avoid my account going to in arrears and am trying desperately to ensure that I will not be debited again at the end of January 2016 as according to my records I should now be in credit at the service provider. PLEASE HELP!!!!!