I had a new Samsung Galaxy Grand Prime locked to the T-Mobile Network. After 2 months of fighting with T-Mobile to get the phone unlocked, T-Mobile finally told me I was unable to have it unlocked as when I purchased it from a re-seller, a non T-Mobile SIM was used. I was very pleased to have CellUnlocker unlock it! It felt like a miracle. I will say though, CellUnlocker said initially it would take 1 - 3 days. I wrote them after 12 days asking why my phone still was locked. My phone was then unlocked within 24 hours. Given the long, drawn out drama with T-Mobile, I am just so grateful to have my phone unlocked I will forgive them the 12 day delay. I will also say, I hate T-Mobile. How ridiculous they could not unlock their own phone when CellUnlocker could unlock the T-Mobile app.