Hi @Dee-12,
Thank you for your post and welcome to our community forums. We're here to help.
I am really sorry to hear that your son's SIM card/handset isn't working as it should. May I ask what kind of handset he's using? Have you also checked the area for any known mast/service issues? You can check by heading here and entering the full post code.
Let us know how you get on.
Thanks,