I used one off ebay however they had 15000 positive feedback.
I rang T-mobile and they say my phone is not blacklisted but its also not been unlocked. I dont know if this is true as when I put my unlock code in it said unlock ok and now when I put another network sim in it doesnt ask for the code. Ive since tried to use an orange sim card in it and this works but I dont know if this is anything to do with the fact that Orange and T-mobile have merged.
If it isnt unlocked then i dont know where to put a new unlock code in.