New User - Need Help!!

Hi Mixvibes crew,
About 6 months ago I bought a refurb Mixvibes Cross system from Guitar Center. I had a lot of things going on so I finally got around to setting it up now. So I have 2 major problems:
A) The Activation CD doesn't have the Cross software. It only has 4 PDF's of instructions
B) Most importantly, the serial number that came with the CD is already registered.
I have no idea what to do, because its too late to return it, but I want to use Cross because it seems so much more appealing than the other software. HELP!!!! Anyone that could help me out on the Mixvibes team?
About 6 months ago I bought a refurb Mixvibes Cross system from Guitar Center. I had a lot of things going on so I finally got around to setting it up now. So I have 2 major problems:
A) The Activation CD doesn't have the Cross software. It only has 4 PDF's of instructions
B) Most importantly, the serial number that came with the CD is already registered.
I have no idea what to do, because its too late to return it, but I want to use Cross because it seems so much more appealing than the other software. HELP!!!! Anyone that could help me out on the Mixvibes team?