Blacklisted N96

I bought an N96 off of E-Bay about 3 months ago. The phone had been unlocked from T-Mobile, and I was using it on Orange.
It worked fine for 3 months and then started displaying the message "Sim Registration Failed" because the phone had been blacklisted. Anyone know how to get around this or what I should do to get it de-blacklisted?

blacklist normally means that someone report the phone stolen, there for you may not be able to use it ever again.

i just bought a samsung m8800 pixon off ebay. It worked for 12 hrs and then got blacklisted. I

was told by my service provider (Orange) that i should contact the original acount holder of the phone, and identify why it has been blaclisted. (Still trying to get hold of him) but i asked orange weather or not the phone could be removed from a blacklist, and they said " it depends on which circumstances the phone was blacklisted) they sugested the most common diognosis was that a contract user would report their phone faulty so they would be sent a new one underr their insurance. They then sell the old one on ebay as apposed to returning it to the provider.

Can my phone be removed from a blacklist? have i bought and expensive paper weight?