NOT REGISTERED ON NETWORK, WHEN I HAVE A CONTRACT!

My Samsung S5 fell and no longer works, so put my sim in a Samsung J5 (I did this a month ago) I have since been struggling to get it working as it gives saying "not registered on network" I called Vodacom and they talked me through the settings to try and connect to mobile networks, but still no success. The consultant told me I need a new sim for this to work. I went to Vodacom today in Greenstone and a consultant tried going through the settings and to connect to mobile networks, but would not work. He put in another sim and the phone worked, so agreed that I need a new sim card (swopped, kept my cell number). He advised I needed to wait for 3 hours before I can put the phone on, which I did in fact wait for 4 hours. On putting the phone on, I still get the same message, "emergency calls only" and "not registered on network" I desperately need my phone to be connected and why after doing what Vodacom tells me to do, still no luc****! I cannot keep phoning Vodacom as I have to use a landline to do this.