MTN unable to protect it clients when SIMcard/phones are ******

One of my phones got ****** yesterday 6 October 2020. I called MTN at the 135 number and requested the operator to block the SIMcard. I did not block the device as I did not have IMEI number on me. I got a SMS from MTN that confirmed that Andile assisted me and they wanted to know if the service was good. Today 7 October 2020 I went to the MTN Woodlands branch to do a SIMSwop. I was informed that I cannot do a SIM swop on the number as the new system did not allow this transaction. A Remedy issue was logged. I was told that this process could take from 2 - 24 hours to resolve. In the MTN shop there was a sign on the window saying that one can send feedback to the service experience to *** and a regional representative will come back within 4 hours. This did not happen. We called the number of the ****** Simcard/phone and it rang. A unknown person answered the phone which indicates that the SIM card was not blocked and is still active. I then called the 135 number again and was told that this telephone number that has been one of my number for twenty year does not show on my profile on the new system which means it cannot be blocked. It does still show on my profile the old system but the call center agent cannot block the SIM on the old system. thus meaning the SIMcard is still active and the ***** is using the Simcard. I do not have recourse to get this Simcard blocked and this is due to MTN's shoddy data transfer from the old to the new system rendering their call center agent unable to assist. I will hold MTN liable for the usage of my airtime and data after I have requested the SIMcard to be blocked on 6 October 202 at 17:16. As a cellphone is an integral part of ones personal and business tools therefor the 24 hours timeline for a SIM swop is unacceptable. If I was able to do the SIMswop at 10:00 this morning this would have finally stopped the usage of this ****** SIMcard.