My phone number hasn't switched

My phone number was scheduled to switch yesterday, and I've received both an email and a text confirming that the switch has occurred. However, whenever I check my number on the iD app, it still shows the temporary number. Similarly, I've tried updating my number in my settings, but iMessage does not seem to accept it (specifically under Send & Receive). I'm pretty sure my old SIM has stopped working, as I've checked the companion app from my previous provider, and it says my account is closed. So, I'm really not sure what to do next. Any help would be greatly appreciated.