I've fixed the setting discrepancy that was causing this so I'd like you to now restart the handset to complete this your end.
To use your mobile data abroad then you need to make sure data roaming is active on the handset itself as well as having the correct APN settings. The basic instructions for doing this can be found here.
But this problem seems to hit a huge number of your customers because all the SIM setup work is presumably done by staff in the Philippines and unfortunately a distressingly high percentage of those staff seem to have very little interest in or clue about what they are doing.
But anyway they shouldn't be able to make this kind of mistake in the first place as the settings should be set automatically the same by a well paid IT worker in the UK who knows what they are doing and then simply replicated by computer transfer to each customer for identical phone models.
Your customers are constantly hit with no data when they visit a new country and yet still Virgin Mobile does not get on top of and permanently fix the prioblem.