Have you tried programing NAM1 and NAM2 with the MetroPCS PRL. Also, set the Home SID on both NAMs to 6503 (or you local SID) and uncheck the NAM Lock box. You might also have luck dialing *22804 or *22806 instead of just *228.
Unless it had been previously MetroFlashed, normally you would have to get the phone MetroFlashed first for the ESN/MEID to be added to their database. I'm VERY surprised that the CSR would add your ESN.
Be on your guard. There are older and fouler things than trolls in the deep subforums.