MTN will not issue refund on incorrectly billed contract

Here is a link to my previous complaint on Hello Peter: https://www.hellopeter.com/summer-mobile/reviews/terrible-service-from-summer-mobile- ********** . This query has still not been resolved. Today when I spoke to Luciano at Summer Mobile he informed that it is MTN's billing department that is holding up the refund of the money that is owed to me. He forwarded me an email form the billing department confirming that the upgrade on my phone has been cancelled but the credit has not been passed. I have been trying to sort out this issue since June. The reference number for this query is ********** 5. Please sort out the refund ASAP.