The IRS says most refunds take 21 days and is just an estimate. But it can be much longer. Only the IRS can tell you when. Once Turbo Tax transmits your return they are done with their part and the IRS doesn’t update Turbo Tax about your return. And there is nothing about getting it 4 days early. Where did you see that? Did you pick to have the Turbo Tax fees deducted from your refund? That is an Extra $40 Refund Processing Service charge (45 in California) and may even add a day or two to get your refund.
What does the irs say? IRS Where's my refund
Today is only 14 days since you filed your tax return. (You said you filed on August 8, and today is August 22.) So your refund is not "taking longer" at all.
The IRS says they pay 9 out of 10 refunds within 21 days. Yours could be the 1 out of 10 that takes longer. And the 21 days applies only to e-filed tax returns that use direct deposit for the refund. It takes longer if you filed by mail or chose to get your refund as a check.
There is nothing you can sign up for to get your refund earlier. You must have misunderstood something.
Money card companies can advertise "up to 4 days early" but it's very misleading. Here are the steps of an ACH transfer:
1. Bank A pre-notifies Bank B of an incoming deposit.
2. Bank B verifies the account number and name, and replies to Bank A "ok to proceed."
3. Bank A actually sends the notification of transfer of funds.
4. Bank B verifies receipt.
5. Transaction "settles" through the ACH clearing house, which is the final verification that Bank A had sufficient funds, that Bank B received them, and everything is settled and finished.
The whole process usually takes 2 business days, not counting weekends.
Some banks might allow you to access your funds after step 1, but other banks might not allow you to access the funds until after step 4 or step 5. So the money card company can let you access your funds at step 1, (even though they have not actually received the money yet) and claim they give you your money "up to" 4 days early (counting weekends).
But the money card can never give you access to a tax refund until the IRS completes at least step 1.
Start by checking "where's my refund".
And incidentally, there are several very good reasons why, if you have a checking account, you should get your refund in your checking account and not do the money card, even if they promise "up to 4 days faster" refund. If you have a checking account, the only reason to use a money card instead is if you are trying to hide the money from someone who has access to your bank account.