I just had a similar issue 2 weeks ago.
What I found worked best was to find a phone on Craigslist I thought would work, ask for the ESN number from the seller, and then call and see if my carrier could use that phone. They were very upfront - 2 of the numbers I called on would work, 1 wouldn't, so I now have a perfectly fine 8330 to replace the missing 8330. Just to be on the safe side, we met at a local carrier store so that they could check out the phone before I handed over the money.
It's a lot quicker to call ahead to your carrier rather than to purchase/say "oops" /resell.