Try the sim in a different phone, if it's the same a new sim is required, call 789 tell them the issue and ask for a replacement tri sim. Also I'd check on the EE website for any faults in your area as we use their network.
Thanks for your post on the Forum. I'm sorry that your SIM is not being detected in your Sony M4 handset. Has this issue been resolved for you now?
If you are still having a problem with the phone, please let me know so that I can look into this further for you. I'll need to take more details from you, so I'll send you a private message. Just click on the envelope icon at the top right of this page.
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