@Catd6 please read THIS and
Use THIS as long as you have find my phone enabled.
You also need to call EE customer services to get your device blacklisted and sim blocked.
and as @BrendonH says do you have insurance? If not and you can not find your device there’s not a lot you can do except purchase a device yourself and request a replacement SIM card from EE. If your a contract customer that contract still has to be paid.
To contact EE Customer Services dial 150 From your EE mobile or 0800 956 6000 from any other phone.
