Okay, so just an updatre everyone.
T-Mobile called me, left a voicemail and explained the same thing customer service told me previously: it is the manufacturers responsibility. I am still waiting on a response from RIM (I filled BBB complaints against both T-Mobile and RIM).
T-Mobile also replied to a fax request I sent them for information regarding their warranty and/or the manufacturers warranty. They stated that the initial documentation was provided with my phone - meaning the warranty document I have is the only form of waranty documentation provided by T-Mobile. This document, if you take the time to read it, makes it clear T-Mobile is responsible for warranty coverage as long as the person making the claim is the person listed on the account the phone was initially activated on. No mention is made that the account must remain active. So I am proceeding with the T-Mobile side of things and filing a claim in Arizona Small Claims court against T-Mobile. I'll see if their lawyers wish to clarify the warranty or somehow show me the elusive part of the warranty that describes how it can be voided for cancelling service.
I'll update this thread as I get more information.