I,m trying to get the advance but credit karma will not let me open a spend account, my husband already has a spend account we file joint it just keeps sending me back

In the FILE tab ... when you ask for the advance, you should be able to indicate you already have a CK account and use that to get the refund. 

When you are asked to sign into your exhisting account DON"T  click on CREATE AN ACCOUNT and you will have the option to open a new account if you wish ...