Unable to do a simple sim swap on pre-paid

I've been trying to do a sim swap for the past few days. My phone was ****** not too long ago and I did a sim swap successfully. I then got a new phone which required a nano sim so I had to buy a new one and do another sim swap to keep my number as it is my business number. I tried 4 times using the instructions on the website with each time saying it cannot process the sim swap. I called the call centre and they said that I cannot do the sim swap if i bought airtime for the sim (the website says to send a sms and without airtime you cannot). I then bought a new sim card and called the call centre and was told that it was escalated to a supervisor and will swap in 2 to 24 hours. After 24 hours, nothing happened. I called again and they said it failed due to the phone being switched off (the previous consultant told me to switch it off) and that I have to wait 30 days to do another swap as it will decline on the system. At this rate I might as well port my number to another network. I cannot sit 30 days with a phone unable to use my number that I've used with all my accounts. Please correct this issue. I'm not buying another sim card just to do this porting again