Sim still on 'Not registered on network after empty promises by Mtn

I am still waiting for MTN to activate my sim card .... which they promised to do in 24hrs last week Thursday 22 March 2018... today is over 72 hrs and my sim card is still in 'Not registered on network' status Talk about service !!!! Mtn have really lost it when it comes to service, every 2nd complain is about their bad Customer service....