I have an unlocked T-Mobile phone that I put my At&t SIM card in. It isn't working just right though. It isn't letting me send or receive multimedia messages and it won't let me lock my phone. When I power it on, it says it's searching for a network but I guess it can't find one. I'm not sure if it's something I can fix, or if I'll just have to live with it. Help me out?
The phone is a Sidekick Danger.