Windows 2012 Terminal Cals

Hi,

Bought a Server from Dell with Windows Server 2008 installed on it with Windows Server 2012 Terminal cals, Now the Terminal cals doesnt accept to downgrade, Please advise what needs to be done, I have triedThe Microsoft Clearinghouse but this doesnt work and when i call the microsoft they dont help as its OEM and Dell says its the right terminal cals.

Regards,

Thomas