iphone bought from local car boot sale is barred carrier said theres nothing they can do 100pounds was spent on phone and 20 pounds on topup beforer realising it was barred whaty to do

i bought an iphone from a local car boot sale which me and my family go to every sturday. (i am 16 years of age) i bought t phone for 100 pounds straightaway because it sounded like an amazing offer for an apples iphone 4 32gb. i got home and everything seemed to be okay with it. it was in good conditiion. the man told me it was locked to the network giffgaff which is ran by 02 so an 02 sim would work on it as well . so i went and bought a 20 pound 02 topup voucher along with an 02 microsim for five pounds and put it ion only to find out that it wouldent work it just kept sohowing no service . so i later on went to by a giffgaff micro sim for the same price and the same thing happend then i went online and emailed 02 and they told me that my phone is barred i didnt know what that meant and they explained it to me saying that it either means the phone has been reported stolen or lost or the previousw owner backed out of thier contract and it was blocked by the carrier and i asked if they could unbarr it and they said that wqont be possible unless the owner calls with the right details . so i waited for the following saturday when me and my family went to the car boot sale only to find that the man i bought it from wasnt there. so now i have spent a total of 130 pounds on a phone that dosent work can someone advice me on what to do. i went online and seemingly apple can unbarr it or send you a new one which is why i am opeining this discussion . like i said i am only 16 i dont work that was all my savings i would hate to have to throw the phone away but at the moment it seems like the onmly oiption . i have tried selling the phone but i have been told it is illegal . if you have any good helpfull sujjestions plleeeeeeeeaaase comment on this discussion

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