Hello~I think I would try another pharmacy, maybe the insurance will pay them, especially if you have not used them before. I am sorry you are having these issues.
Hm. Odd. but I don't think it is illegal. Maybe on their end, they no longer accept your insurance? You can call and talk to a manger at the store. But most pharmacies only reject something if there is really a problem. It's not personal. What is the script for? Pain medication sometimes gets this kind of situation.
The thing to do is to call your insurance company. They'd have the answer if something has changed. Let us know.