Sim Swap

I bought a new phone and still wanted to keep my old number. They told me that since i cant put my old sim in the new phone i should approach the nearest service provider. I did a sim swap at MTN kollonade on the 1st of August and after 24hrs is still didn't go thru, i called 173 and did another sim swap, i went to MTN wonderboom junction on Sunday the 09th and they redid the sim swap again and still it didn't go thru. As of today i have already done sim swap twice since Sunday with mtn call center and yet my old sim card still functions and the new phone is off. Is really frustrating because it seems there is no one that knows whats wrong and the 24hr waiting period just works for them rather than the customer and i really wanted to use my new phone with my old number.