Since it has been over 21 days since your return has been accepted, you will need to contact the IRS to check the status of your refund:
https://www.irs.gov/help-resources/telephone-assistance
Also, have you been checking here? You can check your refund status at the IRS site Where's My Refund. This is for your Federal Return.
https://sa1.www4.irs.gov/irfof/lang/en/irfofgetstatus.jsp
Was your return accepted? Double check the status of your return here:
https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp