Medicare Part D terminated my Mom recently. Can they do this now?

My Mom's employer that she retired from recently required all their retirees to move to an Advantage plan instead of the other options they offered active employees. That conflicted with other insurance coverage she had from my Dads policy and she had to drop her employer coverage because you cant have two policies that contain Part D prescription benefits.
She decided that her Regular Medicare and Medicare supplement plus my Dads coverage better for her because she didnt want to be constrained by a network for doctor choice

Did you have Part D benefits from other insurance?

Possibly...

CVS purchased Aetna and during that purchase there were some requirements placed on the companies to allow the purchase to complete. While I remember the overall info about the acquisition, I have forgotten the specific details regarding how it impacted Silverscript and WellCare. I do remember I ran into some issues with my own Medicare Part D during open enrollment because things were changing during the enrollment period. Maybe this had something to do with the sudden drop in coverage.

Here is one article about Silverscript/WellCare and the purchase: https://www.cnbc.com/2018/09/27/aetna-to-sell-some-medicare-drug-plan-businesses-to-wellcare-health-plans.html that might help explain things.

Why not follow the insurance/Medicare appeals process while waiting for the re-enrollment to come back around?

This companies claims sound a little strange to me. I was in Humana prescription Part D for 4 years - never had to re-enroll. I would always get a letter telling me that the enrollment period started and if I wanted to to stay with them I needed to do nothing. In your case, I would write to the company, as has been suggested and I would also write to your State's insurance commissioner. I do recommend even though it is a pain, that during the enrollment peroid you always review the plans to see if there's a better option out there for you. You need to know what drugs you're going to be taking, what tier they're in and then look at the plans that it offered in your area to find out which ones have the most reasonable cost which, of course, have to be evaluated against the monthly premium.
Good luck in your quest to straighten this out and help your mom.

Since my prescriptions are included in my supplimental, I didn't realize that you need to re-enroll every year for Medicare D. My Mom was on PADD with the State and I don't remember having to do any yearly enrolling.

I would do what is suggested. Hopefully they will allow you to reenroll starting with the 1st of August. If this is done, then you can ask for a form to be reimbursed for any out of pocket. I have done this.

No. You MAIL a letter to Well-armed and state your case. Do not continue doing this on the phone. You have no record of your complaints that way.

I would mail this with a return reciept.

Call the company and throw yourself on their mercy. Explain that mom has dementia and that you did not know about what she had done.