Are you using an iPhone?
I'm having this exact same issue. I bought a sprint phone from a 3rd party, they called and customer service unlocked the phone.
I stuck my sim card in the phone and it said invalid sim (its a mint mobile sim, which is a carrier that uses tmobile). Then I tried an ATT sim from another phone that is working on ATT and I got the same invalid sim message.
I called sprint and they confirmed that it was unlocked.
What needs to be done to get this working?
Hello !! Could you help me please ?
I have the same issue, but with a Galaxy Note 8. I've paid the remaining bill. I have already call 3 times to Sprint and they have told me three times that the phone is unlocked. I have reset to factory and when i put the T-Mobile sim it says that the sim card is invalid.
Please help me !!
I have reported your personal info to have it removed for safety. You will have a notification in the upper right hand corner that is our PM.
Invalid SIM card for me too. S7 Edge. Got confirmation via email that its unlocked. Unlocked in my phone under UICC. Called Sprint was told to go to a Sprint store, did so and was told there they can't do anything more to unlock it. Called Sprint again and am going around in circles.