TriMet sent their retirees a notice which supposedly required immediate action. The notice stated you were to send Medicare Part B premium proof by fax, email or mail to TriMet Attention: Benefits. Questions have arisen as to what document of proof is TriMet looking for and the time frame retirees are required to respond. As of today TriMet is still be accepting your proof. To see an example of what TriMet benefits approved proof is click HERE.