This is pretty clear to me: Page Plus does not support international roaming. It is a wireless provider offering nationwide only service. Please refer to the excerpt below (copy/pasted from their Terms and Conditions):
‘It is possible that under certain circumstances your phone may roam if you are outside of your network coverage area and within the United States. Roaming occurs when a subscriber of one wireless service provider uses the facilities of another wireless service provider. Although there are no additional charges for using the Service while roaming domestically, Page Plus does not guarantee your ability to roam nor the availability and/or the quality of Service. Domestic roaming may be discontinued or changed at any time without notice. Due to Carrier restrictions, Page Plus reserves the right to terminate the Service of any customer whose roaming usage exceeds 50% of their total usage in any three (3) Plan cycles within a 12 month period. International roaming is not offered by Page Plus and is strictly prohibited.’
So, in order to be able to use a cell phone outside the US you should subscribe to another provider.