Voyager Mobile, a four year old Sprint prepaid MVNO, has announced that it is ceasing operations Sept. 9, 2015 at 11 PM EST. Customers should port their number to another carrier before Sept 9. Numbers not ported before that date will be lost forever. To port a phone number, give your new mobile operator your Voyager account name, billing address, account number, and account PIN. Call Voyager at 1-855-33-VOYAGER to get or verify this information.
Unlike several other MVNOs that went out of business in the last couple of years with little warning, Voyager seems to be doing as much as possible to treat its customers fairly. According to a Support page on the Voyager site, customers can request a refund for any days of service lost when they port out by calling 1-855-33-VOYAGER. Customers can also purchase a partial month to keep their line active until their port is complete by calling the same number.
It you want to keep using your Voyager phone with your new provider you need to switch another Sprint MVNO. See Sprint and Sprint MVNO Prepaid Plans Compared for a comprehensive list.