and since your phone was not unlocked, that works in your favor. im guessing that the device is already active on an account with sprint? if so, your best bet is to call sprint and tell them you're phone is not going pass the bootloader after a hard reset. like i said...they'll most likely do a warranty replacement. just tell them you bought a tp2 over a month ago without saying it was from ebay.
or...you can try to see what sprint can do for you by contacting one of the sprint employees that happens to be a member of this forum. i was reading an old thread last night where they identify themselves....but can't remember where in the forum it is. i'll post link to the thread as soon as i find it.
edit...
here's the thread with sprint employee members...
http://forum.ppcgeeks.com/showthread.php?t=60371