I was just watching very detailed podcast on it . You sign up for it when you take a plan out. The carrier bills you monthly (lol,lol). If you don’t pay it the carrier can’t disenrolled you . But they can send to collections after 90 days . Also if you leave the plan and come back to the company at a later date they can start billing you for the past due . How does this work if you sign up for a plan Jan 1st and flip plans to new carrier during oep? Does the carrier forward the billing info to the new carrier ? Wow this is going to be a nightmare. I’m pretty sure most agents will wash there hands of helping with Part D if not being paid .