So 7 years ago you bought the iPhone from iD - yes or no?

Because if you did then there is a good chance it is carrier locked. To unlock it you would need the phone unlocking code (this is nothing to do with a SIM lock), which iD Mobile should be able to give you. If this is the case this explains why the phone doesn’t work on another network. Have you tried one of your children's iD SIMs in the phone since you left iD?

But if it was never bought from iD but another mobile service then they too might have a carrier lock on it, maybe from Three UK.

The reason is, that from around December 2018 and earlier phone providers were allowed to do this. Since then they are not.

And if it is carrier locked this would explain why it doesn’t work on EE. Has EE confirmed your IMEI is blacklisted?

If iD have indeed blacklisted your phone then I am totally confused why they did this if the phone was never provided by them in the first place. Have you taken it into an Apple store for them to look at it?

Hi ​@Ernestine 

We’ll shortly send you a Private Message to your Community account, so we can discuss your issue further. 

To access your messages, click your profile picture in the top right hand corner and then click ‘Private Messages’. 

Alternatively, if you are currently logged in, you can use the following link: https://community.idmobile.co.uk/inbox/overview  

We’ll see you there. 

Tom

Hey there ​@Ernestine, we don’t have a CEO team or manager we can escalate this to, or send you details of I’m afraid.

If you’ve already raised a complaint, and been speaking to them, we’d recommend calling them back for further assistance and advice.

We apologise if you had a poor interaction during your last call, and we sincerely apologise for that.

However, if you’d like further assistance regarding your complaint, we’d recommend re-contacting them directly.

https://www.idmobile.co.uk/help-and-advice/complaints-procedure

Thanks,

Tyler