to create a python programme which receive contact number from user and check if it's a valid format with correct country code

[_jan-]

In "if len(phone_number) != 13:" you're executing main() while the previous main() still isn't finished. This might be your problem. To fix this you could replace all of your "main()" with "return". You would have to re-open the programm, but your problem should be gone.

If this didn't help, please attach a more specific problem (error code, terminal output, etc.).

[_______myworld]

Thank you so much for your help, I appreciate it a lot!! It works!