UNFAIR TREATMENT!

I AM UTTERLY DISSAPOINTED WITH THE SERVICE OF MTN. I bought a new sim card since my old one got damaged. I called the call centre to do a sim swap and my call was put on hold for about an hour with no answer, I then called using my husband's cellphone ans his call was answered withing seconds. I spoke to a lady who told me a sim swap can only be done after 24hours of registering a sim card. Ok so I waited for 24hrs to pass though i was shocked because it was the first time I heard of such. I then called the following day and they put me on hold for about 3hrs. I got irritated and used my colleague's phone and it was answered in seconds. I then asked the lady why they were putting me on hold for that long but they responding quickly to the other phone? The lady said to me its because I am using a new number and I am not as important as those who have old numbers so my call was on hold because they are attending to the old users first regardless of who called first. Why would this be the reason? Shouldn't we all be treated equally ? I have never had such problems before with mtn and i have been with them for more than a decade but now they are telling me all this? I am disappointed