try activating it by dropping the last digit of the IMEI. You might get voice and SMS to work but not 3g.
Also, it may not activate over the air. if that is the case, activate the IMEI as i mentioned about, after the rep says it is active on their system, ask them what the MIN # is and manually program that # into your phone. I'm not sure how it is down on this particular phone, but most phones have dial code that you ent erthat will allow you to access manual input of these values.
let us know how itgoesS