Who is "it"? Did the IRS Where's My Refund site say your refund check had been mailed? Where's My Refund will give you a personalized date after the IRS processes your return and approves your refund.
Confirm the status on the IRS web site: https://www.irs.gov/refunds
If you have waited quite a few days past the date provided by the IRS for the postal service to deliver it, you can start the process to get the check replaced. Use the information on this IRS site: https://www.irs.gov/faqs/irs-procedures/refund-inquiries/refund-inquiries-0
Where did it actually say delivered? I don't think anyone says that except the post office. What exactly did it say? The IRS might say sent or approved.
Turbo Tax will never know if or when the IRS sends your refund. Turbo Tax only transmits your return to the IRS then their part is done. Turbo Tax only shows that the IRS Accepted or Rejected your tax return and gives you an estimated date for your refund.