Have you received an email stating when your funds will be available?
Once accepted, you will receive an email with further instructions on accessing the funds. Check your spam folder for the email. See the TurboTax FAQ here for more information on your Refund Advance.
Please make sure the primary taxpayer information matches exactly the same as your Credit Karma account. Changing any information in one account like your password, phone number, mailing address or email doesn't automatically change it in the other account.