Maybe you're using the prepaid apn that's why your postpaid sim doesn't work on your wifi device.
Try to find the APN from the settings of your wifi device and change it to the postpaid APN.
Have a wonderful day!
After you log in to the Web Management Page Interface, Click on the Settings > Mobile Connection > Click on Profile Management > Change the Profile Name to "MyTattoo Wifi POSTPAID" > Click "Apply". Then restart your Pocket Wifi..
APN : http.globe.com.ph (Prepaid)
both of the above comments are right try to check the APN settings.