Optum Rx has the absolute WORST customer service I have ever had to deal with, and unfortunately, I have to deal with them often. The company's billing system is never straightforward - we regularly receive bills for things that seem to have already been paid. The bills do not have claim numbers on them, so the customer needs to make an assumption for what it is for (which is sometimes unclear, since sometimes they bill at the time of fulfillment and sometimes they don't). Each time this happens, when I call OptumRx customer service to resolve the payment issue, I get a runaround of transfers until someone registers the issue and I am told that it will be resolved. But it never ever ever ever is. Stay away if you can.