iPhone won’t let me ring anyone

I think my son who’s two has pressed something on my phone! It won’t let me ring anyone at all.. it comes up with the number you have called is not recognised! And it says it for every single contact in my list! The numbers are correct! Does anyone know how I can sort this? I’ve restarted my phone completely and turned aeroplane mode on mad off! Literally tried everything! Hoping someone can help please :)

​[Re-Titled by Moderator]