Forget about buying phones on Craigslist or Swappa, or even eBay unless you can pay with a credit card. These scammers know all about how to circumvent the "protection" policies. The sites couldn't care less because they make money from the sale. More scammy sales, more revenue, no problem.
On sites like eBay, you can't change your feedback. I don't know about Swappa. Say you got the phone, left good feedback like "fast shipping, item was like description" and you get screwed 2 months later, you can't go back and report what happened.
If you use Paypal, use a credit card to fund the purchase. Paypal defaults to using your bank account. Then if anything happens and Paypal's like "lol he waited 45 days to scam you, we won't do anything", you do a charge-back and get your money back.
Also, I thought Verizon has the whole ESN thing? Don't you have to unregister the phone's ESN from your account and the new buyer can register it on their account? Then the original owner wouldn't have ownership of the phone anymore and shouldn't be able to report things related to the ESN?
Can someone clarify?