Can't receive calls or texts after receiving new sim due to previous one being stolen

I recently had my phone stolen and had to order a replacement sim card from smarty because of this. After receiving the new sim card, I had issues activating it and had to speak to a couple of people on the live chat to get it working. Eventually they got it to work, but I can only make calls and get mobile data, and can't receive calls or messages at all. If someone calls me it will say that my number is not recognised, and my biggest issue is that I can't log in to all my apps that I need to without verification codes being sent to my number 😣 I have spoke to multiple people on the live chat, and can't seem to get anywhere with it. I'm currently using an android, but my stolen phone was an iPhone. Anyone have any idea what to do?