How can I restore SIM card recognition on my iPhone SE?

Hello. I’ve messed up my phone. I thought I was adding a different esim for the country I am staying in but I obviously didn’t do it correctly and now my phone isn’t recognising the SIM card after I deleted the esim.

I’m still on holiday so have limited option for getting it sorted out but am missing important calls while it’s out of action.

Can anyone tell me what I can do to restore it. I’ve tried removing the SIM and reinstalling it and the usual turning off and on with no success.

I have a 2nd generation S

[Re-Titled by Moderator]