Has any one else ever gotten an Xbox card and it kept saying that this code doesn't exist?

It has to be activated at cash register or its not going to work.

No but take it back it could have been activated b4. Or call company

Don't know anything about this

I don't know the answer to that

Only if it was powered off wrong or power outages ,or poor MSW Ups was plugged into it. Try taking it back if it still does it maybe the slot is dirty or your power is an issue and keep it away from speakers or magnetic fields.