It used to be that, if a product you buy from Amazon drops in price within 7 days, upon request, Amazon would credit you the difference. No longer. Except for TVs, forget about it. But, if the Amazon rep mis-states Amazon's policy thinking Amazon does do price guarantees but it would not apply in this instance, and then tells you Amazon "cannot" do a refund or even an accommodation, and sticks with that position even after you explain that, of course Amazon can choose not to do a refund or an accommodation, but Amazon certainly "can," sure-as-the-sun-comes-up-in-the-East, make any accommodation it wants, you certainly should ask for a supervisor. When you explain to the supervisor that you have now done Amazon a favor by bringing an improperly trained rep to its attention, and you have the option to do a return and re-buy which is a lose/lose for Amazon, it's third-party seller, you should indeed get an accommodation of at least $10. Then, you might as well delete camelcamelcamel from your favorites list.
PS: If you give a bad review to Amazon upon receipt of its email for feedback, you will be encouraged to let them call you or have a chat or send an explanatory email. You might consider writing something like this even if it doesn't produce a further accommodation: "I mistakenly understood that Amazon would match price-drops so I tracked my $267 cellphone purchase on camelcamelcamel.com. When the price dropped by $13, I phoned Amazon. The first rep told me there would be no refund credit because, while the phone was fulfilled by Amazon, it was sold be a third-party and price guarantees applied only if the product was sold by Amazon. She also refused to make any accommodation saying Amazon "cannot" make any accommodation. I then talked to a supervisor who told me Amazon has no price guarantee policy at all whether on products fulfilled by Amazon or even sold by Amazon. He did acknowledge that Amazon "can" make accommodations and he did a $10 accommodation. The whole process took me nearly a half hour on the phone including a more than 10-minute hold waiting for a supervisor. It's been a very frustrating and disappointing process. I strongly suggest that Amazon make clear, if the supervisor is correct, that it does not do any kind of 7-day or other price guarantee, and if he is incorrect, make clear what the policy is. Of course, I could have just returned the phone for a full refund and bought it again at the now lower price, which would be a hassle for me, and a negative for Amazon and its original third-party seller. I also strongly suggest that Amazon take appropriate action with camelcamelcamel.com that it's offering a service that is bound to confuse and frustrate Amazon customers, as it did me." It might not get you any further accommodation though.