Yello service please

Went to Northgate MTN on Monday to upgrade my sons phone. the gentlemen that helped was awesome .. or so we thought, With the new upgrade we needed a nano sim, still no problem as this is normal. Thursday today still no signal on the new phone/sim card. Phoned 808 to query whats going on, try 1 Linda answered told her my problem .. call cut.. Try two.. spoke to clara explained my problem went through the security check AGAIN , sim 'reset' done and whoops call cut.. a bit too convenient.. Try three spoke to Viola who again asked e the security questions because her system doesn't sow I have a security pin that was set up years ago and was accepted by attempt two.. only to be told the SIm swop was never done and there is no way call centre agent number two could have reset the sim card... really MTN.. I am now seriously regretting upgrading this contract... this will be the LAST TIME... YOUR SERVICE NEEDS A REBOOT!!!