Battlefield 2 Complete Edition key

Hey! I recently bought a Battlefield 2 Complete Edition digital copy of the game not from Origin but from Amazon, it accepts my CD Key in the installation but when I try to join a online server it says "CD-Key Invalid" , I am a great fan of the BF series and wanted to give BF2 a try and its really heart breaking to see it doesn't work, many people complain about this, I just bought it today and I have tried every single fix and can't seem to get it to work, please help! I have uninstalled and installed the game three times now and it still doesn't work.