Welcome to the Community Forum, I'm sorry that your mobile service isn't working while abroad in Spain.
Have you been able to check the link that AlexKid recommended? Is this working for you now?
If you're still not able to use your service, please let me know so that I can check this for you. I'll need to take more details from you, so I'll send you a private message. Just check the envelope icon at the top right of this page.
Virgin Media Forum Team
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