Double Deduction and no apology or acknowledgement

On the 15th July 2015 an amount of R 1449,38 was incorrectly deducted. An amount of R 520.02 was refunded on the 22 July 2105. MTN did not apologize or explain the said deductions. As they deducted a higher amount it caused another of my debit orders to be unpaid. After numerous calls I received a reference number *** from Shanice Rayners at the call centre on the 23 July 2015. I have emailed Shanice as the Banking Dept nor Credit Control have still not given me an explanation or a letter of apology for the inconvenience caused. I urgently await a letter from MTN as an apology or explanantion.