"Item not as described" is the crux of the problem, it sounds like that to me. I have found the best way of resolving issues is respectful communication with the seller to work out an acceptable solution. As someone mentions upthread, perhaps the seller still has the other disc, having been mis-filed or something. Always best to try and avoid an adversarial stance in communication, and assume it is not an intentional deception on the part of the seller. Allow room for all parties to save face. I always reserve negative feedback for only worst offenders who refuse to play nice, keeping in mind those individuals are likely to retaliate with negative feedback against me as well, even undeservedly. Good luck and remember, often a little bit of faith and patience can go a long way. One can express dissatisfaction and expect remedy without taking an adversarial position.