SIM SWAP NOT DONE

I requested for a sim swap to be done on five occasions just to be advised that it takes anything from 2 to 24 hours for a sim swap to be done. I could not do the sim swap the first time around I was told that a sim swap cannot be done because the new sim card was activated 72 Hours ago , thats how long I have been trying to do the swap, I had to buy a new sim card only to be told that my old sim card was not ricaed, how i do not know because i used that sim card over more than 6 years. MTN is the worst service provider ever