Second hand iphone 4 unlock

Hello

I was visiting my friends in Ireland, and I have bought a second hand iphone 4. The people told me, that the phone was unlocked, they put few different sims in it, and it worked. So, once i got home, i resored it. And then i found out that the phone was locked to 3. I have contacted 3, but they said they needed the previous users request to unlock it, and I can not get the phone unlocked. So they told me to try to contact apple about this question. So firstly I would like to ask, if it is possible for apple to unlock the phone for me? Because I was tricked and I can not use the phone.. i am very sad now. Thank you for your help.