Can you still use a iphone 5 sprint even if it has Invalid Length?

I bought a sprint iphone 5 on craigslist and i tried to unlock with GPP. The original carrier is Sprint but i want it for Net 10. I did the steps right and i got the signal but then loses it and goes to straight no service. So maybe i thought it had a bad esn (blacklisted) so i went to this website checkesnfree.com and it says INVALID LENGTH? They gave me this definition " The amount of characters entered is invalid". What does that mean? Can i still use it? Or is the Gpp not working?

Added (1). I put the IMEI number and put sprint and it says error credited? Can i still use the phone? It dosent say blacklisted… Help Please

You got taken.

  • Why can't you set full length songs as ringtones on an iPhone? I've never owned an iPhone but i heard you can't set full songs as tingtones, i'm just wondering why? The phone is so advanced, why a full track can't be set as a ringtone! Maybe some of you understand Apple's reasoning on this.
  • Why can I still send texts to other iPhones even though my iPhone has NO sim card? My iPhone stopped recieving calls properly so I've had to put my sim card into a different phone. Why when my mate text me from his iPhone did I receive it still on my iPhone and not the phone with the sim card in. And I was able to text him back from the iPhone but when he called me the little Nokia that I'm using rang… I'll be honest, I really don't understand how iOs stuff works…
  • What is the maximum length for sending video from iphone to iphone? Is 30 seconds too much to send via mms on iphone? Sometimes it says the file is too large or long… I know there are a few apps that let you but do they still get the video even if they don't have the app?
  • Sprint iphone 5 invalid sim card? I recently got an sprint iphone 5 and i've tried to activate it (I already have a number for it) but it says invalid sim card. Do I need to replace the sim or can i just take it to sprint and have them fix it?