Until the OP proves they are in possession of these phones.... consider this SCAM CENTRAL!!!
Add a picture of your brand new iphones for sale with a sheet of paper that has BOTH your username and the most recent block height written on it.
If the OP adds the picture/pictures then I'd use a trusted escrow..... until then, you're considered a scam.
Also, be wary of the fact that if they were stolen or purchased with a stolen credit card and the police were given the serial numbers, expect a knock on the door at some point from the boys in blue.
Too good to be true usually mean too good to be true.

edit:
I have decided to place an order with this gentleman,deal is 509$ BTC once i receive tracking and confirm with UPS that the weight etc matches.
LOL, 4 months ago you are asking for a loan in this community and then suddenly you have $500 worth and willing to take a risk and buy a supposedly original Iphone from someone without any escrow? Best of luck!!!
Instead of sounding like a dickhead please read my reply.
And for your information i do have 500$ for a 700$ phone with basically no risk.
I would not trust anything from this newbie at all. Smells like they are in bed with the OP or they have ZERO common sense. You had a chance to use escrow and didn't. Instead you are going to trust the weight of a package to be your trigger to release funds? I can't shake my head enough at you. Even if this users "claims" they received their item etc it could still be complete BS. DO NOT TRUST the OP or this user.
I appreciate the criticism,i can guarantee you i just messaged the seller however that doesnt really mean much.The seller said this
i will update further once i actually have a tracking number.