Locked serial number on Sprint EVO 3D

[Harleyspringer2]

I purchased a Sprint EVO 3D from Craigslist only to find the phone was activated on the sellers account that owes a large bill. I called Sprint and they said the serial number is locked until the owner pays his bill.
What can I do to unlock the serial number and if I can unlock it will the phone lock itself if I use a different carrier? The seller went incognito on me.

 

[btc0526]

Nope there is no way. You have to flash is to boost or metro pcs