Extremely Poor Service from MTN repairs

Just over a month ago I sent my Samsung A5 to MTN at Clearwater mall for repairs as there was a problem with the battery. The lady who worked there said that the repairs would take anywhere between 7 and 14 working days. One month later and we decided to call MTN and they said that there seems to be a problem with the courier and that the phone has not been dispatched from the repair centre. They said that they would escalate the issue and that we should phone them back the next day. The next day, they still give the same story about the courier and are unable to tell us how long it will take. Even after the third call and one email later, nothing has changed. This is unprofessional and highly frustrating as I have been without a phone for more than a month! How much longer is it going to take? As a customer I was expecting my phone to take no longer than 14 working days and I believe that MTN's "courier problems" should not be made mine or any other customer's for that matter.