SIM disconnected, No answer at Call Centre

I was contacted by Selldirect to upgrade my Telkom Mobile cellphone contract. I specifically requested that I wan t to use my existing SIM card going forward, as I want to continue using my existing iPhone 5, and not the new phone.<br> Today, my SIM card was disconnected. I tried to call both numbers on the Selldirect website, with no answer.<br> This is shocking service. How am I supposed to contact somebody to assist with my cellphone contract and any issues I have?<br> I need you to immediately reactivate my existing SIM card, as I now have no way to make calls or do anything on my phone.