This is what OptumRx does time and again. You either submit new prescriptions or file for refills, you don't receive them, you inquire why and they tell you you owe them some past due from out of the blue and if you want your medication you have to pay up.
You're account online reflects no balance due, with every transaction you have authorized payment, no bill or statement has ever been submitted to you, but now if you want your meds you have to grease the machine. This has just happened to me again last night. A past due balance, I'm told, from March of 2013. This situation is insane.
Doesn't a business have some obligation to make an effort to collect arrears if they want to claim you are delinquent in making payment for services rendered? And how does that work if the services they say have been rendered could have only been rendered after payment has been authorized? People, it's a shell game.
I suggest you not only write to your benefits administrator but to the chamber of commerce and your elected representatives both local and national. These people need to be exposed and you have every right to demand respectful service.