log into your Virgin Mobile account then click on the "Plan and device" tab.
Go to "Manage my services" > "Roaming" needs to be set to ON & "International call barring" needs to be set to OFF
If they are not already, make the change by moving the "switch/tab" in your account.
If you have to make a change to the settings, allow time for your account to update then reboot your phone.(Virgin advise that this may take upto 24 or longer from abroad).
I would periodically turn the phone off/on to see if it finds and selects a network.
You may have to go into the phone's settings and do a manual search for network.
Also check that roaming is enabled on the handset itself.
Here is a useful help page from Virgin: Taking your mobile abroad
If you want to say thanks > click 'Kudos'.Answered your question? > click 'Mark as Helpful Answer' also.
there is no email address.
You could try Virgin's web chat for help: Help and Support - Contact Us > Mobile > Mobile not working > Chat online.
The advisors are often busy though so you may not get connected straight away.(I would recommend keeping the page open and refresh it every few minutes).