Not receiving sms for the last 4 months!!!

My wife took out a top up contract in Sep 2015. Initially then handset was problematic due to software and a faulty camera.We returned the handset, and after an initial assessment, she was given a replacement. After a month, she noticed that she was no longer receiving any sms's. We once again returned the handset to be told it was the settings which were out of sync. The settings were reset, but the problem was not resolved. We then visited the Canal Walk branch on 06/12/2015 where we were assisted by Chastity. She informed us that a sim swop was required to rectify the problem, and that it should be resolved within 24 hours. After this time elapsed, the problem was still not resolved. We have been making a follow up but to no avail. We were last informed that the matter was escalated to the technical division, but we are yet to receive a positive response. We demand that this be rectified, or a working replacement handset be issued!!!