Hi xxmissaxx,
A warm welcome and thanks for posting on our community forums. Can we ask if you set a voicemail pin up in the UK before you travelled abroad?
Any network changes are best done whilst you are connected to a UK network. If they're done abroad we cannot guarantee they'll take effect until your phone connects to a UK network again.
We can try and reset your voicemail pin from our end to see if this does work for you. I will pop you over a private message to take some details from you.
Please click on the purple envelope to accept the chat.
Kind regards Jodi.