My first run-in w/ Medco related to this medication was in 2008. Medco (like most) is biased to generics, and we gave the generic a whirl. It did not work; my MD documented the fact; and I wrote the FDA's generic drug office, which keeps records of these issues. The next time my MD sent in the Rx for the brand name med, a Medco rep called my MD to try to convince him to use the generic. (I know this because he called me immediately afterward to confirm that his records were correct and the generic did not work.) Two days later, a Medco rep called my home at 8:45 pm to tell me I had to switch to the generic or my copay would increase to more than $140 per month. I told the rep that my MD had confirmed the need for the brand name 2 days previous, and meanwhile checked copays on the website, which showed maximum copay for this brand name at $90 per month. I confronted the rep with that information, and he told me I would have to get approval from risk management to use the brand name. So we went around that barn.
A little more than a month ago, Medco incorrectly filled an Rx with the generic. I didn't notice until I opened the bottle several weeks later -- by which time I was no longer insured by Medco. After running me and my doctor around on the telephone for more than an hour on more than 6 different calls, Medco finally informed me that they would not do anything about it. So Medco saves; the local social services dept gets a three-month supply of a generic I can't use; and I wasted a huge amount of time.
Medco's explanation is that the MD failed to DAW the RX. The MD is furious because the RX forms sent by Medco had brand names or generic names at the top, according to what I take, so she finds their forms misleading -- who would think to DAW a set of forms that have been correctly pre-written for brand names or generics?
As far as I'm concerned, Medco is among the lowest of the bottom feeders. They exploit the distances and time involved in required mail-order RX to force medication changes that are to the benefit of their bottom line, not their patients. Did I call us patients? The correct name is profit centers.

If you dislike the terms of your insurance find another insurer. There is no law that says an insurer has to pay for the higher priced medication. Not one. Not all insurances cover everything so this complaint is unfair and unwarranted.