Insulin and Medicare

Animas offered to replace my 5 year old pump under Medicare. Suddenly, my pharmacy "discovered" I used a pump and says it falls under part B now and they can't bill part B, even though they billed part D for 5 years.
Is this legal? Can a pharmacy participate "partially" in Medicare, billing for one and not the other.
Help! I can't afford out of pocket insulin and will have to give up my pump if this is the case.

Sorry I am so late in replying to your post. I experienced the same type of situation when I went on Medicare in August 2010. For a long time I paid my co-pays for my insulin until I read an article on Medicare.gov. Medicare will pay for your insulin if it is used in an insulin pump. It was difficult for me to find a pharmacy who did bill under part B as part B has different codes than part D. I finally ended up using Prescription Solutions. Check the Medicare website so you can be certain of the information.