Continuous faulty billing

Dear Sir<br> We bring this to your attention, and request that you reply in writing as we want to give MTN a fair opportunity to explain these billing discrepancies which we are undoubtedly not prepared to accept.<br> It seems that we are being subjected to unilateral adding of offerings, and then where our debit order is simply being used by MTN to deduct whatever MTN wants to deduct. Please consider the below and revert. If our understanding is incorrect, please indicate why.<br> Notwithstanding endless attempts with MTN to sort out the difficulties emanating from your billing department, we have been unsuccessful to do so.<br> Substantial amounts of time have been spent on telephone calls with MTN to try and resolve this issue and emails but NO satisfactory reply at all.<br> The fixed debit order amount of 2 x R389.01 = R778.02 suddenly changed during March 2015 to 2 x R448.01 = R896.02.<br> Reference numbers with MTN to try and resolve this are, amongst others:<br> 125 222 505 on 23 March 2015