I get that you see that phone as a 'status symbol' because it's expensive and all of the marketing, and how other kids look at you etc etc. The thing is if you didn't buy it and can't afford it then it's a false status.
Also the whole 'status symbol' etc thing is just a money trap designed to keep everyone poor/in debt, but that's something you'll -hopefully- realise as you age.
And that isn't just about that phone, it'd be the same if you won a Ferrari to drive, or a castle to live in. If you can't afford the things to begin with then you can't afford the upkeep of them. When you've been lucky then the clever thing is to sell it on and do something worthwhile with the money.
In a few years time the phone will be basically worthless. Hell, in a few months time it'll be worth a lot less. And you'll be looking back and thinking "Shit, I should've sold it when I had the chance to make some proper money on it instead of trying to be flashy in front of my mates"
Another thing to remember is that in a few years time few -if any at all- of these schoolmates will remember you and your phone. They'll be off living their own lives. And there's the chance that if they do remember it'll be more like "Hey, remember that kid who won the iPhone and would ponce around school with it pretending to be rich? What was their name again?"
I know this advice is going to fall on deaf ears but the smart move here is to sell it, buy another phone, and do something special with the money.
Betting on things is legal in the UK, and we have something called an accumulator. Basically you pick a number of horses/dogs/etc and then choose X number of races.
If what you pick wins the first race then it's automatically put on the second and so on. If one of your picks loses then you lose the lot.
Anyways in the early 90s a mate of mine won a 15 horse accumulator. He put £1 in and won something like £270000. Astonishingly, astonishingly lucky. Especially as he knew nothing about horses and basically picked them all because of their names!!
He talked about expensive holidays or to go to las Vegas to "carry on his winning streak" and buying expensive cars etc. At that time our friend group consisted of about 8 lads and we all sat him down in a pub and all basically said "stop talking like a twat".
It took a bit of time, negotiation, and compromise but in the end he decided to buy a modest house outright, take about £10k for stupid shit, and invest the rest. Which he did.
Within a few years he was basically set for life. House paid for and money from good investments. He gave up his stressful job and got a job working as a school caretaker.
Life took us all in different directions and countries but he is still set up and enjoying life. Never went to las Vegas though, which is probably definitely a good thing!!