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.
