Motorola

I just purchased the MPX220 phone and I have T-mobile service. It says I have the 1.28 software version, I know there is a 1.43 version out, but I can't update my phone with it. Everytime I try it says my phone has the latest software. I called Motorola and they said since the update is for Cingular it won't update my phone because I have T-Mobile. Is there any way around Motorola's B.S? Please help, I am very interested in getting the new software. Thanks