post code for ireland not working need help

Others have posted the same problem. Contact iTunes Support for assistance. See the Apple Support articles below for contact information.   

iTunes Support – world wide 

Apple Support schedule phone call      

If necessary, try Twitter

https://twitter.com/AppleSupport.          People have posted it may take an hour or more to get a response.

Hello.

Thank you for using Apple Support Communities. It sounds like you're experiencing issues attempting to update your billing information. If this is the case, we'd like to look into this with you.

Are you using a specific device to update your billing information? If you update your information using the Apple ID website, does it continue to give you errors?

Apple ID

Feel free to update us. Kind regards.