Best Medicare Part D IVIG Coverage

I have a problem now that Medicare won’t pay for my IVIG as it’s coming from a RX Provider Company instead of the actual manufacturer-so it’s now considered a “drug”. When Baxter was the supplier Medicare paid it almost in full and the rest bounced over to my secondary Blue Cross ( has it’s own prescription plan I use). With the shortage of IVIG and my intense need to have it at the neuro’s every two weeks this RX company can do that. The RX company is charging 65% more too.
As of July my Blue Cross is taking the full amount on and I have a lifetime coverage cap to consider.
So-what Medicare Part D provider is doing the best IVIG coverage price wise for you??
Blue Cross said I could have TWO prescription coverages-no problem adding Part D with Medciare.
Please give any suggestions and even private message me.
Thank you.