Seems like I'm having the same issue as others, I recently left Sprint for another carrier and I took my phone to a new carrier and was given a new sim card. I have spoken with Sprint on numerous occasions to get my phone unlocked to no avail. It has been a tiring process. Right now I have service with a new provider but my phone says "Invalid Sim card". I need help customer service. I have paid off my phone and account is zero balance and I was told that my phone should be unlocked.