My iOS device is not working in my country after using eConnect SIM in Japan.
If you installed our APN profile on your iOS device, you have to remove / uninstall it.
You go to Settings > General > Profile and you can remove our APN profile there.
You can also check our uninstall guide page: https://my.econnectjapan.com/set-up/uninstall
In case you need to set a specific APN (access point name) for your original SIM, please contact your original carrier.