Promise to refund not honored

In response to my first report on this forum, MTN undertook to refund me the incorrectly billed SMS amount of R0,75. This was promised on 24 March 2015. To date, no adjustment has been made to my account. See MTN ***<br> <br> In addition to the above, I expect the VAT on the above amount to be refunded as well.<br> <br> In addition to this, I demand a refund of the amount (plus VAT) that was added to my account for obtaining a specified invoice for the period in which the incorrect charge was made.<br> <br> The refund of the charge for the specified invoice was discussed and agreed with MTN before I agreed to requesting the specified invoice.<br> <br> i.e. I agreed to the charge for the specified invoice, in order to determine which number I allegedly sent an SMS. The agreement (in writing) was that if it was accepted by MTN that I did not send the alleged SMS, I will be refunded the charge for the specified invoice as well. See MTN ***<br> <br> MTN, please honor your commitments and get this issue resolved.<br> <br> Thank you