Hi @ernest4150 
The 3G network is being turned off and this may have happened in your area and the info on the website may not have been updated to refect this
What phone do you have?
Is it on the iD Mobile Approved Handsets list? https://www.idmobile.co.uk/help-and-advice/approved-handsets
Does your handset have VoLTE ability? Is it turned on?
Once you supply more info someone may be able to point you in the right direction. x

Hey there @ernest4150, welcome to Community!

As @Decembersangel72 has kindly advised, it’s likely due to the 3G turn-off that began rolling out recently. You can check if this is the case in your area below:

https://www.three.co.uk/support/network-and-coverage/coverage

Please read more below on what this is, and what to do:

https://community.idmobile.co.uk/3g-200/3g-is-being-switched-off-what-do-i-need-to-do-50979

If you have one of the phones from the below list, then 4G VOLTE and Wi-Fi calling should be able to be selected and work, and calls should still work:

https://community.idmobile.co.uk/help-with-your-phone-206/what-phone-are-compatible-with-the-id-mobile-network-67490

If you have a phone that isn’t on this list, then it may or may not work, but we don’t officially support any phones outside of these and cannot say for sure if it will or not.

If the issue persists after following the troubleshooting above and confirming if your phone is approved, then please let us know here so we can investigate further. If your phone isn't listed above, you'll need to upgrade/get a new phone I'm afraid to receive calls. Texts and data should continue to work either way.

Additionally, if you're using an iPhone that's supported by us, please try the following:

1) Go to settings > Phone > My Number > and check that your phone numbers is showing or correct. If not, please add the correct number and try a call.

2) Turn off iMessage, restart your phone, then try a call and see if this helps.

Thank you,

Tyler