I went thru the samething about a 7 weeks ago. I have 2 XFX GTX 285's in SLI both of them reg. with XFX. One of them went bad just one day started acting crazy (artifacts all of the time). I rma it to XFX and told them what it was doing. They got a hold of me about a week later and asked if I was runing them in SLI because both of them were reg with them, I said yes. They said that they didn't have any of the GTX 285's in stock and didn't know when they would have them. So I said I would wait, I waited for a month and they never did get any of the 285's in stock. They e-mailed me back and said they could send me a XFX 5850 instead. I said no because I was running them in SLI and wanted a 285 back. I asked to speak to a SUP. they said he would e-mail me back. Again several weeks later they e-mailed me and asked if a 5850 would be ok, I again said NO I wanted a 285 back so I could go SLI again, Never did hear from a SUP about all of this. Waited about 2 more weeks and finally gave up on the whole thing, gave in and e-mailed them and said send me the 5850. I got it and it is a awesome card, but I like Nvidia and wanted my 285 setup back. I ended finding somebody on the forums that wanted to trade his XFX 285GTX for the 5850. I found out if you argue with them they will not answer you, or make you wait forever before you get an answer. I would take the card and either sell it or find somebody on the forums that wants to trade with you, if you don't your in for a long wait.
Just my 2 cents worth and my opinion only. I understand your case is different than mine, I was just giving you a heads up about how they operate with RMA's.