Shocking MTN service

I purchased a Black Friday contract online & the SIM card was delivered to me. I read up that you need to port your number before putting in my new SIM card which I have been trying to do however with no luck. I went into a MTN store where I was informed that my new sim had been activated without my consent & there is no way to now port my old number. I find this absolutely ridiculous. Nowhere online when I was filling in my details was I asked or informed about the issue with porting a number when purchasing a contract online. This is totally unacceptable. I refuse to accept that there is no way for me to keep my old number when I haven’t even put the new sim into a phone yet or started using my new contract. If this is the case I would rather terminate my contract and stay with my existing service provider. So much for making things easy by doing things online. And added to this I have phoned 135 a hundred times & no matter what option I select I just get cut off and can not speak to a consultant. And I don’t even know what my number number is even if I wanted it as I was just sent a SIM card with no details! Totally disappointing.