My battery door is loose as well. I called T-Mobile to have them send another battery door to me but as they cannot do such a thing... they are offering the "buyer's remorse program" to me in which I would have to send my phone to them, pay for shipping out of my own pocket to have them send me a new phone after they receive mine. I told the customer service rep that this policy is not what T-Mobile stands for with their "best customer service" and I requested for a supervisor to call me. I should get a call within 24 hours and I'll let you guys know what happened.
Oh and by the way, the reason why they do not want to send the new phone first to me is because "they do not want 2 phones floating around and they want to have insurance that I won't keep both phones"... this is retarded... they can just put a pending charge on my credit card for full price of the phone... whatever that is... to insure that I will send the phone back to them...
There's pics in that thread from a guy that put pieces of rubber band in the back.
I cut squares of masking tape ~.5"x.5" and made two stacks of four squares placed on top of each other. Took off the battery cover and put a stack right by where the tabs on the cover rest on the top of the phone. So basically if you look at the piece of the phone where the camera rests, I put the stacks right after it drops off and goes under the battery cover. Look at the pics on the Crackberry thread and I put the tape where the guy put the two rubber band pieces on the top of the phone.