Ignoring for a second that the only way to unblock a phone is to change the IMEI number, and even having the software to do this can get you five years of porridge....no, it can't be done, the IMEI on this is in a write once memory and can't be changed/repaired.
Come clean and send it back
Take it apart and sell all the bits (screen/housing etc) as spares
Sell it abroad (it's only blocked in the UK)
Sell it in the Pub
(don't do this)
Try and unblock it (REALLY don't do this)
Use it for WiFi access only
Hope this helps.