Help please! Updating unlocked Note 3..

[Garrison Stephens]

Hello, I just bought a third party unlocked Note 3 from Groupon. It was originally a Verizon phone. That being said, it is not allowing me to update my software to the latest version of Android. It says the service is temporarily unavailable, I suppose it's because it needs the Verizon towers to update. How can I update my phone? I love this phone and don't want to return it (I have 30 days to return) Thanks in advance!