The condition of your iPhone is not good ?
There is also a way to repair !
They say that repair. . . however it's a replace to real models .
I think the exchange of latest models is expensive.
However, a few daysneed , the repair will not be able to use the phone.
The following procedure. . .
I take a backup MacBookAir ① iTunes
I reset once ② iPhone
③ I will keep my iPhone, I brought into the Apple repair center
④ model exchange
I restore the backup from MacBookAir in ⑤ iTunes