Hell... Go get a new SIM card from T-mo, see if that works better.

But I do have one question, from your description, it didn't sound like you slid the SIM card into the metal tray and then folded the card and tray down onto the contacts? Or maybe I misread your description.

I popped the little tray off it's hinges before I realized the SIM card actually slides into the metal tray. But I have an excuse for doing that. I've never claimed to be a genius.