I bought a used Galaxy S7. I am NOT a Sprint or Boost customer. I am a T-Mobile customer. I contacted sprint and they said that the phone was a boost phone. The phone came with a Sprint sim card (It has a phone number associated with it and a Sprint username, but it can't make calls or use data) When I start up the phone there is a Sprint Startup Screen. When I go to Settings > Software Updates, under UICC Unlock its says "Your device is locked to Sprint SIMs only" and when I click UICC Unlock it says "Error, The profile update could not be completed. Please try again later. Error: Internal Error (407)" I have the previous owner's name. If anyone can point me in the right direction that would be great!