PM is a prepaid service so they don't issue refundsTry to delay the port until the end of your 90 days plan.Make sure to stop the pre-authorized payments if you have one setup
Follow the following steps to set you APNhttp://productioncommunity.publicmobile.ca/t5/Phones-Hardware/How-do-I-set-up-data-APN-on-my-smartphone/td-p/3