Cards are saved once the transaction completes.
I'd recommend you check whether the vendor has Token on both their Test and Live Sage Pay account. If they have do not have Token, ask them to call Sage Pay on 0845 111 4466.
If you are using Ebizmarts Community Edition (FREE) version of their module, the latest release can be downloaded here.
If you are using the PRO version (chargeable extension) please email Ebizmarts via info@ebizmarts.com as they have excellent support.