I need to change country/region

Why you are not able to change? If you don't see "Change Country or Region," on your device contact Apple Support.

Mere saying couldn't;t change does not give any information to troubleshoot.

It would be better if you can please re-post with a screenshot, in order to understand the phenomenon better. Images / pictures speak louder than words. (Do not provide any personal credentials, such as email id, apple id, IMEI number, Serial Number, Phone number, Order ID, if you are sharing a map ensure your location is not identifiable. etc)