Not sure if this was ever posted so I decided to share it.
I now have a 8320 w/ T-Mobile. Which I love!

I was getting an error everytime I tried to back-up the device and I noticed when it gave me the error it was on browser during the back-up.
So I went to the phone browser and deleted history and it then worked just fine.

ps. T-Mobile gave me my unlock code in one day by email.

Wirelessly posted (Tmob's cheapest BB customer)

I have heard of that issue before but its not common. Thanks for sharing that. And yes Tmobile can be pretty quick with those ublock codes.